doc: number documentation

PR-URL: #356
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

doc/number.md

@@ -1,29 +1,160 @@
 # Number
 
-A Javascript number value.
+`Napi::Number` class is a representation of the JavaScript `Number` object. The
+`Napi::Number` class inherits its behavior from `Napi::Value` class
+(for more info see [`Napi::Value`](value.md))
+
 ## Methods
 
 ### Constructor
 
+Creates a new _empty_ instance of a `Napi::Number` object.
+
+```cpp
+Napi::Number();
+```
+
+Returns a new _empty_ `Napi::Number` object.
+
+### Contructor
+
+Creates a new instance of a `Napi::Number` object.
+
+```cpp
+Napi::Number(napi_env env, napi_value value);
+```
+
+ - `[in] env`: The `napi_env` environment in which to construct the `Napi::Nuber` object.
+ - `[in] value`: The `napi_value` which is a handle for a JavaScript `Number`.
+
+ Returns a non-empty `Napi::Number` object.
+
+ ### New
+
+ Creates a new instance of a `Napi::Number` object.
+
+```cpp
+Napi::Number Napi::Number::New(napi_env env, double value);
+```
+ - `[in] env`: The `napi_env` environment in which to construct the `Napi::Nuber` object.
+ - `[in] value`: The `napi_value` which is a handle for a JavaScript `Number`.
+
+Creates a new instance of a `Napi::Number` object.
+
+### Int32Value
+
+Converts a `Napi::Number` value to a `uint32_t` primitive type.
+
+```cpp
+Napi::Number::Int32Value() const;
+```
+
+Returns the `int32_t` primitive type of the corresponding `Napi::Number` object.
+
+### Uint32Value
+
+Converts a `Napi::Number` value to a `uint32_t` primitive type.
+
+```cpp
+Napi::Number::Uint32Value() const;
+```
+
+Returns the `uint32_t` primitive type of the corresponding `Napi::Number` object.
+
+### Int64Value
+
+Converts a `Napi::Number` value to a `int64_t` primitive type.
+
+```cpp
+Napi::Number::Int64Value() const;
+```
+
+Returns the `int64_t` primitive type of the corresponding `Napi::Number` object.
+
+### FloatValue
+
+Converts a `Napi::Number` value to a `float` primitive type.
+
 ```cpp
-Napi::Number::New(Napi::Env env, double value);
+Napi::Number::FloatValue() const;
 ```
- - `[in] env`: The `napi_env` Environment
- - `[in] value`: The value the Javascript Number will contain
+
+Returns the `float` primitive type of the corresponding `Napi::Number` object.
+
+### DoubleValue
+
+Converts a `Napi::Number` value to a `double` primitive type.
 
 ```cpp
-Napi::Number::Number();
+Napi::Number::DoubleValue() const;
 ```
-returns a new empty Javascript Number
 
-You can easily cast a Javascript number to one of:
+Returns the `double` primitive type of the corresponding `Napi::Number` object.
+
+## Operators
+
+The `Napi::Number` class contains a set of operators to easily cast JavaScript
+`Number` object to one of the following primitive types:
+
  - `int32_t`
  - `uint32_t`
  - `int64_t`
  - `float`
  - `double`
 
-The following shows an example of casting a number to an uint32_t value.
+### operator int32_t
+
+Converts a `Napi::Number` value to a `int32_t` primitive.
+
+```cpp
+Napi::Number::operator int32_t() const;
+```
+
+Returns the `int32_t` primitive type of the corresponding `Napi::Number` object.
+
+### operator uint32_t
+
+Converts a `Napi::Number` value to a `uint32_t` primitive type.
+
+```cpp
+Napi::Number::operator uint32_t() const;
+```
+
+Returns the `uint32_t` primitive type of the corresponding `Napi::Number` object.
+
+### operator int64_t
+
+Converts a `Napi::Number` value to a `int64_t` primitive type.
+
+```cpp
+Napi::Number::operator int64_t() const;
+```
+
+Returns the `int64_t` primitive type of the corresponding `Napi::Number` object.
+
+### operator float
+
+Converts a `Napi::Number` value to a `float` primitive type.
+
+```cpp
+Napi::Number::operator float() const;
+```
+
+Returns the `float` primitive type of the corresponding `Napi::Number` object.
+
+### operator double
+
+Converts a `Napi::Number` value to a `double` primitive type.
+
+```cpp
+Napi::Number::operator double() const;
+```
+
+Returns the `double` primitive type of the corresponding `Napi::Number` object.
+
+### Example
+
+The following shows an example of casting a number to an `uint32_t` value.
 
 ```cpp
 uint32_t operatorVal = Napi::Number::New(Env(), 10.0); // Number to unsigned 32 bit integer