Block Scope and Shadowing in JavaScript

Hello Readers,

• Read this Blog to know about Block Scope and Shadowing .

Block:

• also known as Compound Statement. For Example

{
This is a Block.
}

• Block is used to Combine Multiple JS Statements into One Group.
• We group multiple statements in a Block, so that we can use it where JS expects one Statement.

if(true)   //This statement will give error.

• The if syntax expects any statement after if(true) ...here.

if(true) true //This is correct.

• But what if we want to include multiple statements in if block, Here we use Block {}.

if(true){
  line1
  line2
  more lines ...
}

BlockScope:

• All the variables and Functions accessible inside a scope, so that's why we say let and const are Block Scoped because they are stored in a different memory space reserved for the Block.

Shadowing:

• If we have same Variables outside as well as inside the block. The variable inside the block shadows the outer variables. For Example:

• But Not in case of let or const due to lexical scopping

• vice versa not true!.
• All these programs work same for Arrow Functions too.
• Thanks for Reading the blog, Have a Great Day :)