added bind() function

JavaScript_Advance/bind.js

@@ -0,0 +1,19 @@
+/*The bind() method creates a new function that, when called, has its this keyword set
+to the provided value, with a given sequence of arguments preceding any provided 
+when the new function is called.
+*/
+let module = {
+ x: 42,
+ getX: function() {
+ return this.x;
+ }
+ }
+
+ let unboundGetX = module.getX;
+ console.log(unboundGetX()); // The function gets invoked at the global scope
+ // expected output: undefined
+
+ let boundGetX = unboundGetX.bind(module);
+ console.log(boundGetX());
+ // expected output: 42
+

docs/JavaScript_Advance/bind.md

@@ -0,0 +1,21 @@
+
+*The **bind()** method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.*
+
+ let module = {
+ x: 42,
+ getX: function() {
+ return this.x;
+ }
+ }
+
+ let unboundGetX = module.getX;
+
+ console.log(unboundGetX()); 
+
+> The above function gets invoked at the global scope
+> expected output: undefined
+
+ let boundGetX = unboundGetX.bind(module);
+ console.log(boundGetX());
+
+> expected output: 42