JavaScript - block statement

In this article, we would like to show you block statement in JavaScript.

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{

  // Put your code here

}

Warning:

The block statement was introduced in ES6 (ES2015).

In this example, we use a block delimited by a pair of braces to group statements. The block is "curly brackets"  ({}) and may optionally be labeled.

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var x = 1;

let y = 1;

​

if (true) {

  var x = 2;

  let y = 2;

}

​

console.log('x = ' + x); // 2

console.log('y = ' + y); // 1

Output:

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x = 2

y = 1

Unlike var statement, identifiers declared with let and const do have block scope, which means they are limited in scope to the block in which they were defined.

Example 1

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let x = 1;

{

  let x = 2;

}

​

console.log(x); // 1

Example 2

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const c = 1;

{

  const c = 2;

}

​

console.log(c); // 1

1. block - JavaScript | MDN