feat: 🎸 added closures example

Author: Pratham82

2024 Prep/namaste_js/closures.js

@@ -0,0 +1,40 @@
+/**
+ * * Closure: function along with it's lexical scope bundled together forms a closure
+ *
+ */
+
+/**
+ * The function x() returns the inner function y().
+We assign the result of x() (which is y()) to the variable closureExample.
+We then call closureExample(), which still has access to the variable a due to closure, and it logs 7
+ * 
+*/
+// function x() {
+//   var a = 7
+//   function y() {
+//     console.log(a)
+//   }
+//   return y // Returning the inner function y
+// }
+
+// var closureExample = x() // Now closureExample holds the function y
+// closureExample() // This will log 7
+
+function outest() {
+  var c = 90
+  function outer(b) {
+    function inner() {
+      console.log({ a, b, c })
+    }
+
+    // let a = 80
+    return inner
+  }
+  return outer
+}
+
+let a = 100 // If the reference of a is not found in the whole lexical scope of parent function then, this value of will be considered and logged
+// value of a is not present anywhere then it will be reference error since a is not defined anywhere
+
+const exec = outest()('outerParams')
+exec()