03_scope.js

Learned about Scope in Javascript that what is Global scope and what is block scope, how values of block scope treated outside the curly braces, difference between Global and block scope.

Author: aayushyadavz

03_Basics/03_scope.js

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+/* 3. Scope 
+
+Note: {} This curly braces in every programming language is known as scope.
+eg. function {}, if {} else {}, for {} e.t.c, means it is scope of that function,
+loop, conditional e.t.c. 
+Note: {} Curly braces in Object is Object Declaration. */
+
+if (true) { // (true) states that we will go inside this if statement.
+    let a = 10
+    const b = 20
+    var c = 30
+}
+// Note: The declared variables in "{}" should not exceed "}"
+// console.log(a); // Throw an error that 'a' is not defined
+// console.log(b); // Throw an error that 'b' is not defined
+// Note: It is good that variable a & b are not going outside the scope.
+// console.log(c); // Output: 30
+/* Note: This 30 should not come outside.That's the problem of var keyword.
+
+--------------------------------------------------------------------------------------
+Global Scope, */
+let a = 100
+const b = 200
+var c = 300
+
+// Block Scope,
+if (true) {
+    let a = 10
+    const b = 20
+    var c = 30
+}
+
+console.log(a); // Output: 100
+console.log(b); // Output: 200
+console.log(c); // output: 30
+
+/* Note: Values of Global scope can be available inside {} but values written inside
+{} should not go outside {}
+
+Note: The scope checked in browsers console and the scope checked in our code
+enviroment using node are different. */