updated

ummeabiha · ummeabiha · commit 86f9b59a5143 · 2024-02-14T02:55:43.000+05:00
diff --git a/Destructuring.js b/Destructuring.js
@@ -0,0 +1,32 @@
+let arr = [3, 5, 8, 9, 12, 14];
+// No need to do this:
+// let a = arr[0]
+// let b = arr[1]
+// let [a, b, c, d, ...rest] = arr
+// console.log(a, b, c, d, rest)
+// let [a, , b, ...rest] = arr
+// console.log(a, b, rest)
+let { a, b } = { a: 1, b: 5 };
+// console.log(a, b)
+
+// Spread Operator
+let arr1 = [3, 5, 8];
+let obj1 = { ...arr1 };
+console.log(obj1);
+
+function sum(v1, v2, v3) {
+  return v1 + v2 + v3;
+}
+
+console.log(sum(...arr1));
+
+let obj2 = {
+  name: "Harry",
+  company: "Company xyz",
+  address: "XYZ",
+};
+
+// console.log({ ...obj2, name: "John", company: "ABC" })
+console.log({ name: "John", company: "ABC", ...obj2 }); // This will print the obj2 object without changing any values
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax
diff --git a/JavaScript Notes.txt b/JavaScript Notes.txt
@@ -1,6 +1,41 @@
 script tag must be loaded in last, as it won't recognize the body tag, if defined earlier than it.
 *************************************************************************
+==> WHAT IS JAVASCRIPT???
+- It is a single-threaded language. (can do one task at a time)
 
+- It is a non-blocking language (doesnot make other operations wait, if one operation is taking time for execution such as in setTimeout).
+
+- It is a asynchronous concurrent language (can see non- blocking behaviour of JS).
+
+- JS runtime can do only one operation at a time. (Browser, APIs are not a part of runtime hence we are able to perform multiple operations with the assistance of APIs and browser support)
+
+- It has a call stack, event loop, and a callback queue+ other APIs.
+
+- V8 is JS runtime which has call stack and a heap.
+
+- The heap is used for memory allocation and stack holds the execution context.
+
+- DOM, setTimeout XML Http Request doesnot exist in V8 source code. 
+
+- Task Queue --> As JS can execute one task at a time, the rest tasks are queued waiting to be executed.
+
+- Call Stack --> the order in which operations are executed. All the operations to be executed are stored in a stack, and follows the stack behaviour for e.g.
+
+greeting=()=>{
+  hello=()=>{
+
+  }
+}
+stack order--> greeting(), hello();
+hello() will be executed first and leaves the stack, then greeting() will starts to execute.
+
+- Event Loop --> 
+JS has a runtime model based on event loops, which is responsible for the execution of code, collecting and processing events, and executing sub-tasks.
+pushes the operations from task queue to the call stack.
+
+setTimeout (fun, 0) --> when set timeout is run with 0 parameter, it means that the task should be delayed until other tasks are completed. 
+
+*************************************************************************
 Javascript is a dynamically types language. We do not have to tell the datatype of a variable.
 for e.g. if we are working in python while initializing the variable we have to define its datatype. Whereas, in JS there is no such thing.
 
diff --git a/index.html b/index.html
@@ -8,7 +8,7 @@
 <body>
     
 </body>
-<script src="ErrorHandling.js">
+<script src="RegularExpressions.js">
 
 </script>
 </html>
