04 Scope JS

Learned about Nested Scope & some interesting concepts related to functions executions.

03_Basics/04_scope.js

@@ -0,0 +1,47 @@
+// 4. Nested Scope
+
+function one () {
+    const username = "Ayush"
+
+    function two () {
+        const website = "Youtube"
+        console.log(username);
+        // Note: function two can access the variables of function one
+    }
+    // console.log(website); // Output: Error
+    // Note: We cannot access the website variable outside function two
+
+    two()
+}
+one()
+/* Output: Ayush
+Note: In nested function child can access parent variables. 
+
+--------------------------------------------------------------------------*/
+if (true) {
+    const username = "Ayush"
+    if (username === "Ayush") /* (true) */ {
+        const website = " Youtube"
+        console.log(username + website);
+        // We can access username variable in child if statement.
+    }
+    // console.log(website); // Output: Error
+    // Note: We cannot access website variable outside the scope. 
+}
+// console.log(username); // Output: Error
+// Note: We cannot access username variable outside the scope.
+/* Output: Ayush Youtube 
+
+**************************** Interesting ***********************************/
+console.log(addone(5));
+
+function addone (num) {
+    return num + 1
+} // Output: 6
+
+
+// console.log(addtwo(5));
+
+const addtwo = function (num){
+    return num + 2
+} // Output: error