@nejs/basic-extensions is a JavaScript library that provides a collection of essential extensions to built-in JavaScript objects like Array, Object, Function, and Reflect. These extensions are designed to enhance the native capabilities of JavaScript objects, providing developers with additional utility methods for common tasks and improving code readability and efficiency.
-
Array Extensions: Adds convenience methods to JavaScript arrays, like
firstandlast, for easy access to the first and last elements. -
Object Extensions: Introduces utility functions to the Object class, such as methods for checking object types and manipulating properties.
-
Function Extensions: Enriches the Function class with methods to identify function types, such as arrow functions, async functions, and bound functions.
-
Reflect Extensions: Extends the Reflect object with advanced property interaction methods, including checks for the presence of multiple or specific keys.
Install @nejs/basic-extensions using npm:
npm install @nejs/basic-extensionsOr using yarn:
yarn add @nejs/basic-extensionsImport the desired extensions in your JavaScript project:
import { ArrayPrototypeExtensions } from '@nejs/basic-extensions';
// Use the Array extensionsimport { FunctionExtensions } from '@nejs/basic-extensions';
// Use the Function extensions- FunctionExtensions
- isAsync
- isAsyncGenerator
- isBigArrow
- isBound
- isClass
- isFunction
- isGenerator
- ObjectExtensions
- stripTo
- getKey
- concat
- contains
- every
- find
- findLast
- length
- map
- reduce
- some
- ReflectExtensions
- StringExtensions
- SymbolExtensions
- ArrayPrototypeExtensions
- object
- constructor
- isAccessor
- isData
- isDescriptor
- configurable
- configurable
- enumerable
- enumerable
- writable
- writable
- value
- value
- get
- get
- boundGet
- set
- set
- boundSet
- hasObject
- object
- object
- for
- applyTo
- toObject
- toPrimitive
- toStringTag
- for
- getData
- getAccessor
- base
- accessor
- data
- isDescriptor
- isData
- isAccessor
- flexible
- enigmatic
- intrinsic
- transparent
- SHARED_KEYS
- ACCESSOR_KEYS
- DATA_KEYS
- maskAs
- maskAsString
- maskAsNumber
- GenericMask
- StringMask
- NumberMask
- RefSet
- RefMap
- isValidReference
- Deferred
- promise
- reject
- resolve
- settled
- AsyncIterable
- AsyncIterator
- Iterable
- Iterator
- mapEach
The FunctionExtensions class is a patch applied to the built-in JavaScript
Function constructor. It extends Function with additional utility methods
for determining the specific type or nature of function-like objects. These
methods allow developers to distinguish between classes, regular functions,
async functions, and arrow functions in a more intuitive and straightforward
manner. This class is part of the @nejs/extension library and enhances the
capabilities of function handling and introspection in JavaScript.
Determines if a given value is an asynchronous function. It checks if the
value is an instance of Function and if its string representation
includes the keyword 'Async'. This method is particularly useful for
identifying async functions.
valueany The value to be checked.
Returns boolean Returns true if the value is an async function,
otherwise false.
The function checks if a given value is an async generator function
valueany Thevalueparameter is the value that we want to check if it is a generator function.
Returns boolean true if the value is an instance of a function and
its string tag is 'AsyncGeneratorFunction', otherwise it returns false.
Checks if a given value is an arrow function. It verifies if the value is
an instance of Function, if its string representation includes the '=>'
symbol, and if it lacks a prototype, which is a characteristic of arrow
functions in JavaScript.
valueany The value to be checked.
Returns boolean Returns true if the value is an arrow function,
otherwise false.
Determines if a given value is a bound function. Bound functions are
created using the Function.prototype.bind method, which allows setting
the this value at the time of binding. This method checks if the value
is an instance of Function, if its string representation starts with
'bound', and if it lacks a prototype property. These characteristics
are indicative of bound functions in JavaScript.
valueany The value to be checked, typically a function.
Returns boolean Returns true if the value is a bound function,
otherwise false. Bound functions have a specific format in their
string representation and do not have their own prototype property.
Determines if a given value is a class. It checks if the value is an
instance of Function and if its string representation includes the
keyword 'class'. This method is useful for distinguishing classes from
other function types in JavaScript.
valueany The value to be checked.
Returns boolean Returns true if the value is a class, otherwise
false.
Checks if a given value is a regular function. This method verifies if
the value is an instance of Function, which includes regular functions,
classes, and async functions but excludes arrow functions.
valueany The value to be checked.
Returns boolean Returns true if the value is a regular function,
otherwise false.
The function checks if a given value is a generator function
valueany Thevalueparameter is the value that we want to check if it is a generator function.
Returns boolean true if the value is an instance of a function and
its string tag is 'GeneratorFunction', otherwise it returns false.
Determines if a given value is an asynchronous function. It checks if the
value is an instance of Function and if its string representation
includes the keyword 'Async'. This method is particularly useful for
identifying async functions.
Returns boolean Returns true if the value is an async function,
otherwise false.
The function checks if a given value is an async generator function
Returns boolean true if the value is an instance of a function and
its string tag is 'AsyncGeneratorFunction', otherwise it returns false.
Checks if a given value is an arrow function. It verifies if the value is
an instance of Function, if its string representation includes the '=>'
symbol, and if it lacks a prototype, which is a characteristic of arrow
functions in JavaScript.
Returns boolean Returns true if the value is an arrow function,
otherwise false.
Determines if a given value is a bound function. Bound functions are
created using the Function.prototype.bind method, which allows setting
the this value at the time of binding. This method checks if the value
is an instance of Function, if its string representation starts with
'bound', and if it lacks a prototype property. These characteristics
are indicative of bound functions in JavaScript.
Returns boolean Returns true if the value is a bound function,
otherwise false. Bound functions have a specific format in their
string representation and do not have their own prototype property.
Determines if a given value is a class. It checks if the value is an
instance of Function and if its string representation includes the
keyword 'class'. This method is useful for distinguishing classes from
other function types in JavaScript.
Returns boolean Returns true if the value is a class, otherwise
false.
Checks if a given value is a regular function. This method verifies if
the value is an instance of Function, which includes regular functions,
classes, and async functions but excludes arrow functions.
Returns boolean Returns true if the value is a regular function,
otherwise false.
The function checks if a given value is a generator function
Returns boolean true if the value is an instance of a function and
its string tag is 'GeneratorFunction', otherwise it returns false.
ObjectExtensions is a patch for the JavaScript built-in Object class.
It adds utility methods to the Object class without modifying the global
namespace directly. This patch includes methods for key validation, object
type checking, and retrieving the string tag of an object. These methods
are useful for enhancing the capabilities of the standard Object class
with additional utility functions.
The function checks if a value is either undefined or null.
valueany The parameter "value" is a variable that can hold any value.
Returns boolean true if the value is either undefined or null,
and false otherwise.
Checks to see if the supplied value is both an object, and has the
appropriate symbol defined.
valueany the value to determine if it contains a definedSymbol.toStringTagdefined.
Returns any true if the symbol is defined, false otherwise
Retrieves the string tag of an object. The string tag is a representation
of the object's type, as defined by its Object.prototype.toString
method. This utility method is helpful for getting a more descriptive
type of an object than what is returned by the typeof operator,
especially for custom objects.
valueany The object whose string tag is to be retrieved.strictboolean if this is set to true, undefined will be returned whenever a supplied object does not have aSymbol.toStringTagdefined, period. if false, the default, (optional, defaultfalse)
Returns string The string tag of the object, indicating its type.
Determines the type of the given value based on its string tag. This method
uses Object.getStringTag to obtain the string tag of the value, which
represents its more specific type (e.g., Array, Map, Set) rather than just
'object'. The method then maps this string tag to the corresponding type
present in the provided owner object, which defaults to globalThis.
This utility method is especially useful for identifying the specific
constructor or class of an object, beyond the basic types identified by
the typeof operator.
valueany The value whose type is to be determined.ownerobject The object in which to look up the constructor corresponding to the string tag. Defaults toglobalThis, which covers global constructors likeArray,Object, etc. (optional, defaultglobalThis)
Returns (Function | object | null | undefined) Returns the constructor or
type of the value based on its string tag. For 'Null' and 'Undefined',
it returns null and undefined, respectively. For other types, it
returns the corresponding constructor (e.g., Array for arrays) if
available in the owner object.
Determines if the provided value is an object. This method checks whether
the value is an instance of Object or if its type is 'object'. It's a
utility method for type-checking, ensuring that a value is an object
before performing operations that are specific to objects.
valueany The value to be checked.
Returns boolean Returns true if the value is an object,
otherwise false.
Checks to see if the supplied value is a primitive value.
valueany the value to test to see if it is a primitive value type
Returns any true if the object is considered widely to be a primitive value, false otherwise.
Checks if the given value is a valid key for an object. In JavaScript, a valid key can be either a string or a symbol. This method is useful for validating object keys before using them in operations like setting or getting object properties.
valueany The value to be checked.
Returns boolean Returns true if the value is a valid object key
(string or symbol), otherwise false.
Strips an object down to only the keys specified. Optionally, any accessors can be made to retain their context on the source object.
objectobject the object to pare downkeysArray<(string | symbol)> the keys that should appear in the final reduced objectbindAccessorsboolean if this value is true then any accessors from the source object will continue to have theirthisvalue bound to the source. If the getter or setter on that object is defined using an arrow function, this will not work as intended. (optional, defaulttrue)
Returns object an object containing only the keys and symbols
specified in the keys parameter.
Strips an object down to only the keys specified. Optionally, any accessors can be made to retain their context on the source object. This is a passthrough to the static Object.stripTo function
keysArray<(string | symbol)> the keys that should appear in the final reduced objectbindAccessorsboolean if this value is true then any accessors from the source object will continue to have theirthisvalue bound to the source. If the getter or setter on that object is defined using an arrow function, this will not work as intended. (optional, defaulttrue)
Returns object an object containing only the keys and symbols
specified in the keys parameter.
The function getKey returns the key associated with a given value
in a map.
valueany The value parameter is the value that you want to find the corresponding key for in the map.strictThe "strict" parameter is a boolean value that determines whether strict equality (===) or loose equality (==) should be used when comparing the "value" parameter with the values in the entries of the object. If "strict" is set to true, strict equality will be used. (optional, defaulttrue)
Returns any the key associated with the given value. If a matching key is found, it is returned. If no matching key is found, null is returned.
Merges multiple iterables into the set. Each element from the iterables is added to the set, ensuring uniqueness of all elements. This method mutates the original set.
iterables...Iterable One or more iterable objects (like Set or Array) whose elements will be added to the set.
Checks to see if any value within the Set loosely equals the supplied
value.
valueany any value that might be loosely equal to an item in the set, as opposed to Set.has which is the equivalent of a strict or triple equals (===) check
Returns boolean true if any value within the set is loosely equal to
the supplied value, false otherwise
Checks if every element in the set passes the test implemented by the provided function. The function is called with each element of the set. Note: Since sets do not have indices, the index parameter is always NaN.
everyFnFunction The function to test each element. Receives the element, index (always NaN), and the set itself.thisArgObject? Optional. Value to use asthiswhen executingeveryFn.
- Throws TypeError If
everyFnis not a function.
Returns boolean True if every element passes the test, false otherwise.
Finds the first element in the set satisfying the provided testing function. If no elements satisfy the testing function, undefined is returned. The function is called with each element of the set. Note: Since sets do not have indices, the index parameter is always NaN.
findFnFunction The function to execute on each element. It receives the element, index (always NaN), and the set itself.thisArgObject? Optional. Value to use asthiswhen executingfindFn.
- Throws TypeError If
findFnis not a function.
Returns any The first element that satisfies findFn, or undefined.
Finds the last element in the set satisfying the provided testing function. If no elements satisfy the testing function, undefined is returned. The function is called with each element of the set in reverse order. Note: Since sets do not have indices, the index parameter is always NaN.
findFnFunction The function to execute on each element. It receives the element, index (always NaN), and the set itself.thisArgObject? Optional. Value to use asthiswhen executingfindFn.
- Throws TypeError If
findFnis not a function.
Returns any The last element that satisfies findFn, or undefined.
A getter property that returns the number of elements in the set.
This is an alias for the size property of the set.
Returns number The number of elements in the set.
Creates a new array populated with the results of calling the provided function on every element in the set. The function is called with each element of the set. Note: Since sets do not have indices, the index parameter is always NaN.
mapFnFunction The function to execute on each element. It receives the element, index (always NaN), and the set itself.thisArgObject? Optional. Value to use asthiswhen executingmapFn.
- Throws TypeError If
mapFnis not a function.
Returns Array A new array with each element being the result of the
mapFn.
Applies a function against an accumulator and each element in the set to reduce it to a single value. The function is called with each element of the set. Note: Since sets do not have indices, the index parameter is always NaN.
reduceFnFunction The function to execute on each element. It receives the accumulator, element, index (always NaN), and the set itself.initialValueany The initial value to start reducing from.thisArgObject? Optional. Value to use asthiswhen executingreduceFn.
- Throws TypeError If
reduceFnis not a function.
Returns any The reduced value.
Tests whether at least one element in the set passes the test implemented by the provided function. The function is called with each element of the set. Note: Since sets do not have indices, the index parameter is always NaN.
someFnFunction The function to test each element. It receives the element, index (always NaN), and the set itself.thisArgObject? Optional. Value to use asthiswhen executingsomeFn.
- Throws TypeError If
someFnis not a function.
Returns boolean True if at least one element passes the test, false otherwise.
The ReflectExtensions class is a patch applied to the built-in JavaScript
Reflect object. It extends Reflect with additional utility methods that
enhance its capabilities. These methods provide more advanced ways of
interacting with object properties, such as checking for the presence of
multiple keys at once (hasAll) or verifying if at least one specified key
exists in an object (hasSome). This class is part of the @nejs/extension
library and is designed to offer these extended functionalities in a way
that is consistent with the existing Reflect API, making it intuitive for
developers who are already familiar with standard reflection methods in
JavaScript.
The function checks if an object has all the specified keys.
objectTheobjectparameter is the object that we want to check if it has all the specified keys.keys...any Thekeysparameter is a rest parameter, which means it can accept any number of arguments. In this case, it is expected to receive multiple keys as arguments.
Returns any a boolean value.
Fetches all descriptors of an object, including those mapped to a symbol descriptor value.
objectobject the object from whose descriptors need to be retrieved.
- Throws TypeError if the supplied
objectis null or not an object a TypeError exception will be thrown
Returns object with keys mapped to object descriptors
The function checks if an object has at least one of the specified keys.
objectTheobjectparameter is the object that we want to check for the presence of certain keys.keys...any Thekeysparameter is a rest parameter, which means it can accept any number of arguments. These arguments are the keys that we want to check if they exist in theobject.
Returns any The function hasSome returns a boolean value indicating whether
at least one of the keys provided as arguments exists in the given object.
Retrieves an array of [key, descriptor] pairs for each property of the
provided object. This method is akin to Object.entries but includes
property descriptors instead of the property values. It's useful for cases
where you need detailed information about properties, including their
configurability, enumerability, and accessors.
objectobject The object whose property entries are to be retrieved.
Returns Array An array of [key, descriptor] pairs, where each pair consists of the property name (key) and its descriptor. Returns an empty array if the input is not a valid object.
Retrieves an array of values from the property descriptors of the given
object. This method works similarly to Object.values but operates on
property descriptors instead. It's useful when you need the values of
properties including getters, setters, and other descriptor-specific
attributes.
objectobject The object whose property values are to be retrieved.
Returns Array An array of values extracted from the object's property
descriptors. The values correspond to the value attribute in each
property's descriptor. Returns an empty array if the input is not a valid
object.
StringExtensions is a patch for the JavaScript built-in String class. It
adds utility methods to the String class without modifying the global namespace
directly. This patch includes methods for key validation, object type checking,
and retrieving the string tag of an object. These methods are useful for
enhancing the capabilities of the standard String class with additional
utility functions.
The isString method does exactly what one would it expect. It returns
true if the string matches typeof or instanceof as a string.
valueany checks to see if thevalueis a string
Returns boolean true if it is a String, false otherwise
SymbolExtensions is a patch for the JavaScript built-in Symbol class. It
adds utility methods to the Symbol class without modifying the global namespace
directly. This patch includes methods for key validation, object type checking,
and retrieving the string tag of an object. These methods are useful for
enhancing the capabilities of the standard Symbol class with additional
utility functions.
The isSymbol method does exactly what one would it expect. It returns
true if the string matches typeof or instanceof as a symbol.
valueany checks to see if thevalueis a string
Returns boolean true if it is a Symbol, false otherwise
Returns true if the supplied value is a Symbol created using
Symbol.for().
valueany assumption is that the supplied value is of type 'symbol' however, unlessallowOnlySymbolsis set totrue,falsewill be returned for any non-symbol values.allowOnlySymbolsboolean true if an error should be thrown if the supplied value is not of type 'symbol' (optional, defaultfalse)
Returns any true if the symbol is registered, meaning, none of the spec
static symbols (toStringTag, iterator, etc...), and no symbols
created by passing a value directly to the Symbol function, such as
Symbol('name')
A function that returns true if the symbol is not registered, meaning,
any of the spec static symbols (toStringTag, iterator, etc...), and
any symbols created by passing a value directly to the Symbol function,
such as Symbol('name').
valueany assumption is that the supplied value is of type 'symbol' however, unless allowOnlySymbols is set to true, false will be returned for any non-symbol values.allowOnlySymbolsboolean true if an error should be thrown if the supplied value is not of type 'symbol' (optional, defaultfalse)
Returns any true if the symbol is not registered, meaning, any of the
spec static symbols (toStringTag, iterator, etc...), and any symbols
created by passing a value directly to the Symbol function, such as
Symbol('name')
Returns any true if the value in question is both a symbol and has
returns undefined if passed to Symbol.keyFor
The ArrayPrototypeExtensions patch extends the prototype of the built-in
JavaScript Array with additional properties for convenience and improved
readability. By applying this patch, all array instances gain new getter
properties first and last, which provide quick access to the first and
last elements of the array, respectively. This enhancement simplifies common
operations on arrays and makes code more expressive and concise.
Sometimes defining even a short function for the invocation of find
can be troublesome. This helper function performs that job for you. If
the specified element is in the array, true will be returned.
valueany the value to search for. This value must triple equals the array element in order to return true.
Returns any true if the exact element exists in the array, false otherwise
The findEntry function searches the entries of the object and returns
the [index, value] entry array for the first matching value found.
findFnfunction a function that takes the element to be checked and returns a boolean value
Returns any if findFn returns true, an array with two elements, the first
being the index, the second being the value, is returned.
A getter property that returns the first element of the array. If the
array is empty, it returns undefined. This property is useful for
scenarios where you need to quickly access the first item of an array
without the need for additional checks or method calls.
Returns any The first element of the array or undefined if the array
is empty.
A getter property that returns the last element of the array. It
calculates the last index based on the array's length. If the array is
empty, it returns undefined. This property is beneficial when you need
to access the last item in an array, improving code readability and
avoiding manual index calculation.
Returns any The last element of the array or undefined if the
array is empty.
An optionally associated object, usually the parent from which the descriptor was taken, or undefined if none was able to be derived.
Type: object
Constructs a Descriptor instance which wraps and manages an object property descriptor. The constructor can handle an existing descriptor object or create a new one based on an object and a property key.
object(object | Descriptor) The target object or an existing Descriptor instance. If it's an object, it is used in conjunction withkeyto create a descriptor. If it's a Descriptor instance, it is used directly as the descriptor.key(string | symbol)? The property key for which the descriptor is to be created. This parameter is ignored ifobjectis a Descriptor instance. Ifkeyis an object andobjectis a valid descriptor,keyis treated as the associated object.
- Throws Error Throws an error if the constructed descriptor is not valid.
Detects whether or not this instance is an accessor object descriptor
Returns boolean true if this object has a getter or setter and is not a data descriptor
Detects whether or not this instance is an data object descriptor
Returns boolean true if this object has a value property and is not an accessor descriptor
Detects whether or not this instance is a valid object descriptor
Returns boolean true if this descriptor store is a valid descriptor
Getter around the configurable object descriptor property of
this instance of Descriptor.
Returns boolean a boolean value or undefined if the internal descriptor store is invalid.
Sets the configurable value of this object. If the internal descriptor
store store is invalid, the value is thrown away
valueboolean the value to set for theconfigurabledescriptor property. If this value is not abooleanit will be converted to one
Getter around the enumerable object descriptor property of
this instance of Descriptor.
Returns boolean a boolean value or undefined if the internal descriptor store is invalid.
Sets the enumerable value of this object. If the internal descriptor
store is invalid, the value is thrown away
valueboolean the value to set for theenumerabledescriptor property. If this value is not abooleanit will be converted to one
Getter around the writable object descriptor property of
this instance of Descriptor.
Returns boolean a boolean value or undefined if the internal descriptor store is invalid.
Sets the writable value of this object. If the internal descriptor
store is invalid, the value is thrown away
valueboolean the value to set for thewritabledescriptor property. If this value is not abooleanit will be converted to one
Getter around the value object descriptor property of
this instance of Descriptor.
Returns any any value stored in this descriptor
Sets the value value of this object. If the internal descriptor
store is invalid, the value is thrown away
valueany the value to set for thevaluedescriptor property.
Getter around the get object descriptor property of
this instance of Descriptor.
Returns function a function if the getter for this descriptor is
defined or undefined if the internal descriptor object or the getter
is undefined.
Sets the get value of this object. If the internal descriptor
store is invalid, the value is thrown away
valuefunction the getter function for this descriptor
Retrieves the get function for this accessor and binds it to the object from which the descriptor was derived, if that value is set. Otherwise this method is identical to the get accessor.
Returns function the getter if one is defined. If possible this
getter will be bound the associated and previously set object.
Getter around the set object descriptor property of
this instance of Descriptor.
Returns function a function if the setter for this descriptor is
defined or undefined if the internal descriptor object or the setter
is undefined.
Sets the set value of this object. If the internal descriptor
store is invalid, the value is thrown away
valuefunction the setter function for this descriptor
Retrieves the set function for this accessor and binds it to the object from which the descriptor was derived, if that value is set. Otherwise this method is identical to the set accessor.
Returns function the setter if one is defined. If possible this
setter will be bound the associated and previously set object.
The function checks the descriptor's associated object has been set on this
instance of Descriptor.
Returns boolean true if the object property has been set,
false otherwise
Returns the descriptor's associated object value. This is usually the
parent object from which the descriptor was derived. If the value is preset
it will be returned. Undefined will be returned otherwise
Returns object the associated object for this descriptor or undefined if it has not yet been set.
Sets the descriptor's associated object value. This is usually the
parent object from which the descriptor was derived.
valueobject sets the object for which this descriptor is to be associated with.
The function returns a string representation of a descriptor object with additional information about its type when used in the NodeJS repl.
depthnumber Thedepthparameter is used to specify the maximum depth to which nested objects and arrays will be formatted. If the depth is exceeded, the output will be truncated with ellipses.optionsobject Theoptionsparameter is an object that contains various configuration options for theinspectfunction. These options can be used to customize the output of the inspection.inspectfunction Theinspectparameter is a function that is used to convert an object into a string representation. It is typically used for debugging purposes or when displaying an object's properties.
Returns any a string that represents a descriptor. The string includes the type of the descriptor (either "Accessor" or "Data") and the result of inspecting the descriptor object using the provided options and depth.
Take the descriptor defined by this objects values and apply them to the specified object using the specified key.
objectobject the object to apply this descriptor toforKey(string | symbol) the string or symbol for which this descriptor will abe appliedbindAccessors(optional, defaultfalse)
Converts this Descriptor class instance into a basic object descriptor that is accepted by all the standard JavaScript runtime methods that deal with object descriptors.
bindAccessors(boolean | object) iftrue, a non-fatal attempt to bind accessor getter and setter methods is made before returning the object. IfbindAccessorsis truthy and is also an object, this is the object the accessors will be bound to. If the value is falsy or if the descriptor instance represents a data descriptor, nothing happens. (optional, defaultfalse)
Returns object the object instance's basic object representation as a descriptor.
Converts this descriptor object into a base representation
hintstring one ofstring,numberor default;
Returns any if the hint is 'string', then a string identifying the enum
and its type is returned. number will always be NaN since it is incoret
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
Shorthand for Object.getOwnPropertyDescriptor()
objectobject a non-null object instancekey(string | symbol) a symbol or string referencing which key on the object to return a descriptor for.wrap(optional, defaultfalse)
Returns any an object descriptor for the requested field or null
The function getData retrieves the value of a property from an object
if it exists and is a data property.
objectobject The "object" parameter is the object from which we want to retrieve data.property(string | symbol) Thepropertyparameter is the name of the property that you want to retrieve the data from.
Returns any either the value of the specified property if it exists and is a data property, or undefined if the property does not exist or is not a data property.
The function getAccessor checks if an object has a getter/setter accessor
for a given property and returns the accessor functions if found.
objectTheobjectparameter is the object from which we want to retrieve the accessor for a specific property.propertyThepropertyparameter is the name of the property for which we want to get the accessor.
Returns any an object that contains the getter and setter functions for the specified property of the given object. If the property is an accessor property (defined with a getter and/or setter), the returned object will also have additional properties such as "accessor" and "descriptor". If the property is not found or is not an accessor property, the function returns undefined.
The function returns an object with enumerable and configurable properties based on the input parameters.
enumerableA boolean value indicating whether the property can be enumerated (listed) when iterating over the object's properties. (optional, defaultfalse)configurableTheconfigurableparameter determines whether the property can be deleted or its attributes can be modified. Ifconfigurableis set totrue, the property can be deleted and its attributes can be changed. Ifconfigurableis set tofalse, the property cannot be deleted and (optional, defaultfalse)
Returns any An object with the properties enumerable and configurable is
being returned. The values of these properties are determined by the
arguments passed to the base function.
The function "newAccessor" creates a new property descriptor object with a getter and setter function, along with optional enumerable and configurable flags.
-
getterThe getter parameter is a function that will be used as the getter for the property. It will be called when the property is accessed. -
setterThesetterparameter is a function that will be used as the setter for the property. It will be called whenever the property is assigned a new value. -
nullObject *getter: A function that will be used as the getter for the property. (optional, defaultDescriptor.base())null.enumerablenull.configurable
Returns any an object with properties "get", "set", "enumerable", and "configurable".
The function "newData" creates a new data object with customizable properties.
-
valueThe value parameter represents the value that will be assigned to the property. -
writableThewritableparameter determines whether the value of the property can be changed. Ifwritableis set totrue, the value can be changed. Ifwritableis set tofalse, the value cannot be changed. (optional, defaulttrue) -
nullObject *value: The value to be assigned to the property. (optional, defaultDescriptor.base())null.enumerablenull.configurable
Returns any an object with properties value, enumerable, writable, and
configurable.
The function checks if an object is a likely an object descriptor in JavaScript. This is determined as an object with some of the known descriptor keys (e.g. enumerable, configurable, value, writable, get, or set). Technically, any object could serve as a descriptor but this function only returns true if known descriptor keys are found.
objectTheobjectparameter is the object that we want to check if it is a descriptor.
Returns any a boolean value.
The function checks if a given property or descriptor is a data property.
brie
object_orProppropertydescriptor_orPropThedescriptor_orPropparameter can be either a descriptor or a property name.objectTheobjectparameter is the object that you want to check for data properties.
Returns any a boolean value. It returns true if the descriptor object
has any keys that match the DATA_KEYS array, otherwise it returns
false.
The function checks if a given property descriptor or property of an object is an accessor.
object_orPropThedescriptor_orPropparameter can be either a descriptor object or a property name.propertyTheobjectparameter is the object that you want to check for accessor properties.
Returns any a boolean value. It returns true if the descriptor or property passed as an argument is an accessor descriptor, and false otherwise.
A base descriptor (new for each read) that is both enumerable and configurable
Returns any The method flexible is returning the result of calling the
base method with the arguments true and true.
A base descriptor (new for each read) that is not enumerable but is configurable
Returns any The method enigmatic is returning the result of calling
the base method with the arguments false and true.
A base descriptor (new for each read) that is neither enumerable nor configurable
Returns any The code is returning the result of calling the base method with
the arguments false and false.
A base descriptor (new for each read) that enumerable but not configurable
Returns any The method is returning the result of calling the base
method with the arguments true and false.
The function returns an array of shared descriptor keys.
Returns any An array containing the strings 'configurable' and 'enumerable'.
The function returns an array of accessor descriptor keys.
Returns any An array containing the strings 'get' and 'set' is being returned.
The function returns an array of data descriptor keys.
Returns any An array containing the strings 'value' and 'writable' is being returned.
Transforms an object to mimic a specified prototype, altering its type conversion and inspection behaviors. This function is especially useful for creating objects that need to behave like different primitive types under various operations.
objectObject The object to be transformed.classPrototypeoptionsprototype(Function | Object) The prototype or class to emulate. If a function is provided, its prototype is used. Defaults to String.prototype. (optional, defaultString.prototype)toPrimitiveFunction A function defining how the object should be converted to a primitive value. It receives a type hint ('number', 'string', or 'default') and the object, returning the primitive value. (optional, default(hint,val)=>String(val))
Returns (Object | null) The transformed object, or null if neither a class nor a prototype could be derived from the provided prototype parameter.
Masks an object as a string-like object by setting its prototype to String and defining how it converts to primitive types. This is particularly useful when an object needs to behave like a string in certain contexts, such as type coercion or logging.
objectObject The object to be masked as a string.stringKeystring The object property key used for the string representation. Defaults to 'value'. (optional, default'value')toPrimitiveFunction? Optional custom function for primitive conversion. If omitted, a default function handling various conversion hints is used.
Returns (Object | null) The string-masked object, or null if the object doesn't have the specified stringKey property.
Masks an object as a number-like object. This allows the object to behave like a number in operations like arithmetic and type coercion. It sets the prototype to Number and defines custom conversion behavior.
objectObject The object to be masked as a number representation. Defaults to 'value'.numberKeytoPrimitiveFunction? Optional custom function for primitive conversion. If not provided, a default function handling different conversion hints is used.
Returns (Object | null) The number-masked object, or null if the object doesn't have the specified numberKey property.
Generates options for generic masking of an object, providing defaults for prototype and toPrimitive function if not specified.
-
optionsObject The options object including prototype, targetKey, and toPrimitive function.options.prototypeoptions.targetKey(optional, default'value')options.toPrimitive
Returns Object The options object with defaults applied as necessary.
Generates options for string masking of an object, providing a default toPrimitive function if not specified.
targetKeystring The object property key for string representation.toPrimitiveFunction Custom function for primitive conversion.
Returns Object Options for string masking.
Generates options for number masking of an object, providing a default toPrimitive function if not specified.
targetKeystring The object property key for number representation.toPrimitiveFunction Custom function for primitive conversion.
Returns Object Options for number masking.
Extends Set
RefSet class extends the standard Set object to manage a collection of WeakRef objects. It provides additional functionality such as objectification of values and various utility methods.
Unlike standard Sets or Arrays, RefSet stores weak references to objects, allowing them to be garbage-collected if there are no other references to them. This behavior is different from Arrays and standard Sets, which maintain strong references to their elements.
Method to control whether the RefSet should objectify its values. When objectifying, primitive values (number, string, boolean, bigint) are converted to their respective object types, which allows them to be used as WeakRef targets.
setObjectificationboolean Flag to enable or disable objectification. (optional, defaulttrue)
Returns RefSet The current RefSet instance to allow method chaining.
Returns the state indicating whether or not RefSet will attempt to
convert non-valid primitives into targets that are valid input for
new WeakRef object instances. If this value is false then no
objectification will occur.
Returns boolean The current state of objectifyValues.
Setting this value to true, will cause all added values to the Set to
be analyzed for validity as a candidate to be wrapped in a WeakRef
object. If true, and if possible, the object will be turned into an
Object variant first. This will also enable less rigid variable
comparison in the .has() method (i.e. == instead of ===).
valueboolean The new state to set for objectifyValues.
Overrides the add method of Set. Adds a value to the RefSet, converting it
to a WeakRef. Throws an error if the value is not a valid WeakRef target
(e.g., null, undefined, or a registered symbol). If objectifyValues is
enabled, an attempt to convert primitives to their object variants will be
made. These are numbers, strings, boolean values and big integers.
valueany The value to be added to the RefSet.
- Throws TypeError If the value is not a valid WeakRef target.
Adds multiple values to the RefSet. The supplied values should be
iterable and truthy. This function defers to .add() for its logic so
each value from the supplied collection of values will also be subject
to the criteria of that function.
valuesIterable An iterable of values to add to the RefSet.
- Throws TypeError If the supplied values are falsey or non-iterable.
Removes all elements from the RefSet that have been garbage collected (i.e., their WeakRef no longer points to an object).
Returns RefSet The current RefSet instance to allow method chaining.
Executes a provided function once for each value in the RefSet. The callback function receives the dereferenced value, the value again (as RefSet doesn't use keys), and the RefSet itself. This method provides a way to iterate over and apply operations to the values stored in the RefSet, taking into account that they are weak references and may have been garbage-collected.
forEachFnFunction Function to execute for each element. It takes three arguments: element, element (again, as RefSet has no key), and the RefSet itself.thisArgany Value to use asthiswhen executingforEachFn.
Iterate over the items in the set and pass them to the supplied
function ala Array.prototype.forEach. Note however, there are no
indexes on Sets and as such, the index parameter of the callback
will always be NaN. Subsequently the array or third parameter
will receive the set instance rather than an array.
forEachFnfunction the function to use for each element in the set.thisArgobject thethisargument to be applied to each invocation of theforEachFncallback. Note, this value is unable to be applied if theforEachFnis a big arrow function
Returns an iterator for the values in the RefSet. Each value is dereferenced from its WeakRef before being returned. This method allows iterating over he set's values, similar to how one would iterate over values in a standard Set or Array, but with the understanding that the values are weakly referenced and may no longer exist (in which case they are skipped).
Returns Iterator An iterator for the values.
Returns an iterator for the keys of the RefSet. In RefSet, keys and
values are identical, so this method behaves the same as values(). It
provides compatibility with the standard Set interface and allows use in
contexts where keys are expected, despite RefSet not differentiating
between keys and values.
Returns Iterator An iterator for the keys.
Determines whether an element with the specified value exists in the
RefSet. For non-objectified sets, this method checks if the dereferenced
values of the set include the specified value.
For objectified sets, it uses the contains method which accounts for
the objectification. This method differs from standard Set has in that
it works with weak references and considers objectification settings.
valueany The value to check for presence in the RefSet.
Returns boolean True if an element with the specified value exists in the RefSet, false otherwise.
Checks if the RefSet contains a value that is equal to the specified
value. This method is used primarily in objectified RefSets to determine
the presence of a value, taking into account objectification. It differs
from the has method in that it's tailored for sets that have
transformed their primitive values into objects, whereas has is more
general-purpose.
valueany The value to search for in the RefSet.
Returns boolean True if the RefSet contains the value, false otherwise.
Creates a new array with all elements that pass the test implemented by
the provided function. This method iterates over each element,
dereferences it, and applies the filter function. Unlike Array filter,
the callback receives the dereferenced value and not an index or array,
reflecting the non-indexed nature of RefSet. Useful for selectively
creating arrays from the set based on certain conditions, especially when
dealing with weak references.
filterFnFunction Function to test each element of the RefSet. The function receives the dereferenced value.thisArgany Value to use asthiswhen executingfilterFn.
Returns Array A new array with the elements that pass the test.
Returns the value of the first element in the RefSet that satisfies the
provided testing function. Similar to Array find, this method iterates
over the RefSet, dereferencing each value and applying the testing
function. The non-indexed nature of RefSet is considered, as the
callback does not receive an index. This method is useful for finding a
specific element based on a condition.
findFnthisArgany Value to use as this when executing findFn.
Returns any The value of the first element in the RefSet that satisfies the testing function, or undefined if none found.
Returns any the dereferenced value if found, or undefined otherwise
Creates a new array or RefSet with the results of calling a provided
function on every element in the calling RefSet. This method dereferences
each value, applies the mapFn, and collects the results. If toRefSet is
true, a new RefSet is returned; otherwise, an array. This method
differs from Array.map in handling weak references and the potential to
return a new RefSet instead of an array.
mapFnFunction Function that produces an element of the new array orRefSet, taking three arguments.thisArgany Value to use as this when executing mapFn.toRefSetboolean Determines if the output should be a newRefSet(true) or an array (false).mirrorObjectificationboolean IftrueandtoRefSetistrue, the newRefSetmirrors the objectification setting of the original.
Returns (Array | RefSet) A new array or RefSet with each element being
the result of the mapFn.
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
Extends Map
RefMap class extends the standard Map object to manage a collection of WeakRef values mapped to strong keys. It provides additional functionality such as objectification of values and various utility methods.
Unlike standard Maps or Objects, RefMap stores weak references to objects, allowing them to be garbage-collected if there are no other references to them. This behavior is different from Maps and standard Objects, which maintain strong references to their elements.
args...any
Method to control whether the RefMap should objectify its values. When objectifying, primitive values (number, string, boolean, bigint) are converted to their respective object types, which allows them to be used as WeakRef targets.
setObjectificationboolean Flag to enable or disable objectification. (optional, defaulttrue)
Returns RefMap The current RefMap instance to allow method chaining.
The function converts a JavaScript Map object into a regular JavaScript object, handling invalid keys by converting them to strings.
Returns object an object; keys that are not either a String or a
Symbol will be converted to a string.
Returns the state indicating whether or not RefMap will attempt to
convert non-valid primitives into targets that are valid input for
new WeakRef object instances. If this value is false then no
objectification will occur.
Returns boolean The current state of objectifyValues.
Setting this value to true, will cause all set values to the Map to
be analyzed for validity as a candidate to be wrapped in a WeakRef
object. If true, and if possible, the object will be turned into an
Object variant first.
valueboolean The new state to set for objectifyValues.
The get function retrieves a value from a map and returns it, or returns a
default value if the value is null or undefined. The actual retrieved value
is a dereferenced WeakRef. If the result is undefined and this is not the
expected response, it is likely the value has been garbage collected.
keyany The key parameter is the key of the value you want to retrieve from the data structure.defaultValueany ThedefaultValueparameter is the value that will be returned if the key does not exist in the map or if the value associated with the key has been garbage collected (i.e., it no longer exists).
Returns any The method is returning the value associated with the given key. If the value is not found or if it has been garbage collected (deref() returns null), then the defaultValue is returned.
Overrides the set method of Map. Adds a value to the RefMap,
converting it to a WeakRef. Throws an error if the value is not a
valid WeakRef target (e.g., null, undefined, or a registered
symbol). If objectifyValues is enabled, an attempt to convert
primitives to their object variants will be made. These are numbers,
strings, boolean values and bigints.
keyany Thekeyto be set on theRefMapvalueany The value to be associated with thekey
- Throws TypeError If the value is not a valid WeakRef target.
Sets multiple values at a single time. The format is an array of array
or rather an array of Object.entries (for example,
[[key1,value1], [key2,value2]]). For each entry pair, if the length
is not 2, either missing a key or value, it will be skipped.
entriesvaluesIterable An iterable of values to add to the RefMap.
- Throws TypeError If the supplied values are falsey or non-iterable.
Returns RepMap returns this to allow for chaining
Removes all elements from the RefMap that have been garbage collected (i.e., their WeakRef no longer points to an object).
Returns RefMap The current RefMap instance to allow method chaining.
Executes a provided function once for each value in the RefMap. The callback function receives the dereferenced value, the value again (as RefMap doesn't use keys), and the RefMap itself. This method provides a way to iterate over and apply operations to the values stored in the RefMap, taking into account that they are weak references and may have been garbage-collected.
forEachFnFunction Function to execute for each element. It takes three arguments: element, element (again, as RefMap has no key), and the RefMap itself.thisArgany Value to use asthiswhen executingforEachFn.
Iterate over the items in the map and pass them to the supplied
function ala Map.prototype.forEach. Note however, there are no
indexes on Maps and as such, the index parameter of the callback
will always be the value's key. Subsequently the array or third
parameter will receive the map instance rather than an array.
forEachFnfunction the function to use for each element in the set.thisArgobject thethisargument to be applied to each invocation of theforEachFncallback. Note, this value is unable to be applied if theforEachFnis a big arrow function
Returns an iterator for the values in the RefMap. Each value is dereferenced from its WeakRef before being returned. This method allows iterating over he set's values, similar to how one would iterate over values in a standard Map or Array, but with the understanding that the values are weakly referenced and may no longer exist (in which case they are skipped).
Returns Iterator An iterator for the values.
Determines whether an element with the specified value exists in the
RefMap. For non-objectified sets, this method checks if the dereferenced
values of the map include the specified value.
For objectified sets, strict is set to false which uses loose
equality to allow for things like Object(5) to equal 5. This is important
because otherwise primitives could not be weakly referenced. In the grand
scheme of things, this is only useful if the objectified value is the
one being referenced.
valueany The value to check for presence in the RefMap.strictboolean iftrue, the default, then the supplied value is hard compared to the dereferenced value (===). Iffalse, then a loose comparison is used (==) (optional, defaulttrue)
Returns boolean True if an element with the specified value exists in the RefMap, false otherwise.
The filter function filters the entries of a RefMap object based on
a given filter function. The dereferenced entries of the values of the map
will be passed to the function rather than a WeakRef itself.
A new resulting entry set will be generated and a new RefMap will be made
from these entries and returned. Note that this function never returns
null
filterFnfunction ThefilterFnparameter is a function that will be used to filter the entries in theRefMap. It will be called with three arguments: the value of the current entry, the key of the current entry, and theRefMapitself. The function should returntruethisArgobject ThethisArgparameter is an optional argument that specifies the value to be used asthiswhen executing thefilterFnfunction. It allows you to explicitly set the context in which thefilterFnfunction is called. IfthisArgis not provided, `this
Returns array The filter method is returning an array of filtered map
entries
The find function iterates over a map and calls a given function on
each value, returning the first value for which the function returns
a truthy value.
The function signature of findFn is
function findFn(value, key, map)
'value' is passed to findFn up to two times; first with the WeakRef
value, second with the result of WeakRef.deref. If findFn
returns true for either of these the dereferenced value will be
returned from the call to RefMap.find.
key represents the key object that the value is mapped to.
map is simply a reference to this map.
findFnfindFnis a function that will be called for each element in the map. It takes three arguments:ref,key, andmap; whererefis the value of the current element in the map,keyis the key of the current element, andmapis a reference to the instance being searched.thisArgThethisArgparameter is the value to be used as thethisvalue when executing thefindFnfunction. It allows you to specify the context in which thefindFnfunction should be called.
Returns any the first dereferenced value that satisfies the condition
specified by the findFn function. If no value satisfies the condition,
it returns null.
Creates a new array or RefMap with the results of calling a provided
function on every element in the calling RefMap. This method dereferences
each value, applies the mapFn, and collects the results. If toRefMap is
true, a new RefMap is returned; otherwise, an array. This method
differs from Array.map in handling weak references and the potential to
return a new RefMap instead of an array.
mapFnFunction Function that produces an element of the new array orRefMap, taking three arguments.thisArgany Value to use as this when executing mapFn.toRefMapboolean Determines if the output should be a newRefMap(true) or an array (false).mirrorObjectificationboolean IftrueandtoRefMapistrue, the newRefMapmirrors the objectification setting of the original.
Returns (Array | RefMap) A new array or RefMap with each element being
the result of the mapFn.
The function returns an iterator that iterates over the entries of an object, dereferencing any weak references.
Returns Iterator A new iterator object is being returned.
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
A static method to check if a given value is a valid target for a WeakRef.
valueany The value to check for validity as a WeakRef target.
Returns boolean True if the value is a valid WeakRef target, false otherwise.
Extends Promise
Deferreds, which were first introduced by jQuery for browsers in the early
2000s, are a way to manage asynchronous operations. They have been widely
used and replicated by engineers since then. Although the Promise class in
modern JavaScript provides a static method called withResolvers that
returns an object with similar properties to a Deferred, it is not directly
supported by Node.js.
const withResolvers = Promise.withResolvers()
Reflect.has(withResolvers, 'promise') // true
Reflect.has(withResolvers, 'resolve') // true
Reflect.has(withResolvers, 'reject') // true
This Deferred class extends the Promise class, allowing it to capture the
value or reason for easy access after resolution, akin to
Promise.withResolvers. As it extends Promise, it is
'thenable' and works with await as if it were a native Promise. This
allows seamless integration with code expecting Promise-like objects.
optionsobject see above for examples on supported options, but when supplied, the constructor can take instructions on how to auto resolve or reject the deferred created here.
When the Deferred is settled with Deferred.resolve, the value
passed to that function will be set here as well.
Type: any
When the Deferred is settled with Deferred.reject, the reason
passed to that rejection will also be stored here.
Type: any
Returns a boolean value that indicates whether or not this Deferred has been settled (either resolve or reject have been invoked).
Returns boolean true if either Deferred.resolve or
Deferred.reject have been invoked; false otherwise
Accessor for the promise managed by this Deferred instance.
This getter provides access to the internal promise which is controlled by the Deferred's resolve and reject methods. It allows external code to attach callbacks for the resolution or rejection of the Deferred without the ability to directly resolve or reject it.
Returns Promise The promise controlled by this Deferred instance.
Resolves the Deferred with the given value. If the value is a thenable (i.e., has a "then" method), the Deferred will "follow" that thenable, adopting its eventual state; otherwise, the Deferred will be fulfilled with the value. This function behaves the same as Promise.resolve.
valueany The value to resolve the Deferred with.
Returns Promise A Promise that is resolved with the given value.
Rejects the Deferred with the given reason. This function behaves the same as Promise.reject. The Deferred will be rejected with the provided reason.
reasonany The reason to reject the Deferred with.
Returns Promise A Promise that is rejected with the given reason.
A getter for the species symbol which returns a custom DeferredPromise class. This class extends from Deferred and is used to ensure that the constructor signature matches that of a Promise. The executor function passed to the constructor of this class is used to initialize the Deferred object with resolve and reject functions, similar to how a Promise would be initialized.
Returns DeferredPromise A DeferredPromise class that extends Deferred.
The promise backing this deferred object. Created when the constructor
runs, this promise is what all Promise.prototype functions are routed
to.
Type: Promise
The reject() resolver that will be assigned when a new instance is
created. Invoking this function with or without a reason will cause
the deferred's promise to be settled.
Type: function
The resolve() resolver that will be assigned when a new instance is
created. Invoking this function with or without a value will cause
the deferred's promise to be settled.
Type: function
When either Deferred.resolve or Deferred.reject are called,
this property is set to true. Its current status at any time can be
queried using the Deferred.settled getter.
Type: boolean
The AsyncIterable class extends the concept of Iterable to asynchronous operations. It allows creating iterable objects where each element can be an asynchronous entity, like a Promise. This class is particularly useful when dealing with asynchronous data sources, such as API responses, file reading in chunks, or any other data that is not immediately available but arrives over time.
elementsOrFirstElement(Iterable | AsyncGeneratorFunction | Promise | any) An iterable object, an async generator function, a Promise, or the first element.moreElements...(Promise | any) Additional elements if the first argument is not an iterable or an async generator function.
Implements the async iterable protocol. When an instance of AsyncIterable
is used in a for await...of loop, this async generator function is
invoked. It yields each element as a Promise, allowing asynchronous
iteration. Elements that are not Promises are automatically wrapped in
a resolved Promise to ensure consistency.
Returns AsyncGenerator An async generator that yields each element as a Promise.
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
Checks if a given value is an async iterable. This method determines if
the provided value has a Symbol.asyncIterator property that is an async
generator function. It's a precise way to identify if the value conforms
to the async iterable protocol using an async generator function.
Note: This method specifically checks for async generator functions. Some async iterables might use regular async functions that return an async iterator, which this method won't identify.
valueany The value to be checked for async iterability.
Returns boolean Returns true if the value is an async iterable implemented using an async generator function, false otherwise.
Being able to create a compliant AsyncIterator around any type of
iterable object. This can be wrapped around any type of object that
has a [Symbol.asyncIterator] property assigned to a generator
function.
asyncIterable(object | AsyncGeneratorFunction) any object that has a[Symbol.asyncIterable]property assigned to a generator function or an async generator function itself.
Returns a new Array derived from the iterable this object
wraps.
Returns array a new Array generated from the wrapped
iterable. The method is generated from using an async for of
loop.
Returns the actual iterable object passed to the constructor that created this instance.
Returns object the object containing the [Symbol.iterator]
The function retrieves the next value in the iterator. If the
the iterator has run its course, reset() can be invoked to
reset the pointer to the beginning of the iteration.
Returns any the next value
Resets the async iterator to the beginning allowing it to be iterated over again.
The existence of this symbol on the object instances, indicates that
it can be used in for(.. of ..) loops and its values can be
extracted from calls to Array.from()
Returns AsyncIterable this is returned since this object is already conforming to the expected JavaScript AsyncIterator interface
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
The Iterable class is designed to provide a convenient way to create synchronous
iterable objects. It can be initialized with either an array or individual elements.
This class implements the iterable protocol, allowing instances to be used with
for...of loops and other standard JavaScript iteration mechanisms.
elementsOrFirstElement(Iterable | any) An iterable object or the first element.moreElements...any Additional elements if the first argument is not an iterable.
Implements the iterable protocol. When an instance of Iterable is used
in a for...of loop or spread syntax, this generator function is invoked
to yield the elements one by one in a synchronous manner.
Returns Generator A generator that yields each element of the iterable.
Provides access to the elements as a standard array. Useful for scenarios where array methods and behaviors are needed.
Returns Array An array containing all the elements of the iterable.
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
Checks if a given value is an iterable. This method determines if the
provided value has a Symbol.iterator property that is a generator
function. It's a precise way to identify if the value conforms to the
iterable protocol using a generator function.
Note: This method specifically checks for generator functions. Some iterables might use regular functions that return an iterator, which this method won't identify.
valueany The value to be checked for iterability.
Returns boolean Returns true if the value is an iterable implemented using a generator function, false otherwise.
Being able to create a compliant Iterator around any type of iterable
object. This can be wrapped around any type of object that has a
[Symbol.iterator] property assigned to a generator function.
iterableobject any object that has a[Symbol.iterator]property assigned to a generator function.mapEachfunction when providedmapEachis a callback that takes an entry as input and receives one as output.
Returns a new Array derived from the iterable this object
wraps.
Returns array a new Array generated from the wrapped
iterable. The method is generated from Array.from()
Returns the actual iterable object passed to the constructor that created this instance.
Returns object the object containing the [Symbol.iterator]
The function retrieves the next value in the iterator. If the
the iterator has run its course, reset() can be invoked to
reset the pointer to the beginning of the iteration.
Returns any the next value
Resets the iterator to the beginning allowing it to be iterated over again.
The existence of this symbol on the object instances, indicates that
it can be used in for(.. of ..) loops and its values can be
extracted from calls to Array.from()
Returns Iterator this is returned since this object is already conforming to the expected JavaScript Iterator interface
Ensures that the constructor of this object instance's name is returned if the string tag for this instance is queried
Returns string the name of the class
A private function that when provided has the following signature:
function mapEach(entry) -> entry. This allows any changes to be made
to each element, conditionally and programmatically, as needed before
they are returned to the called code.
Contributions to @nejs/basic-extensions are always welcome. Please refer to our contributing guidelines for more information on how to report issues, submit pull requests, and more.
@nejs/basic-extensions is licensed under the MIT License. See the LICENSE file for more details.