ES6: the keyword let in examples

The keyword let allows us to create block scopes in JavaScript. Let’s see some examples.

Block scope

Using var.

var me = 'James Bond';
if(true) {
var me = 'Chuck Norris';
}
console.log(me);
// Chuck Norris
view raw es6-let-01.js hosted with ❤ by GitHub

Using let.

let me = 'James Bond';
if(true) {
let me = 'Chuck Norris';
}
console.log(me);
// James Bond
view raw es6-let-02.js hosted with ❤ by GitHub

Loops

Using var.

for(var i = 0; i < 5; i++) {
// ...
}
console.log(i);
// 5
view raw es6-let-03.js hosted with ❤ by GitHub

Using let.

for(let i = 0; i < 5; i++) {
// ...
}
console.log(i);
// ReferenceError: i is not defined
view raw es6-let-04.js hosted with ❤ by GitHub

Duplidated variables

Using var.

var country = 'Brazil';
//..
//..
//..
var country = 'Belgium';
console.log(country);
// Belgium
view raw es6-let-05.js hosted with ❤ by GitHub

Using let.

let country = 'Brazil';
//..
//..
//..
let country = 'Belgium';
console.log(country);
// Duplicate declaration 'country'
view raw es6-let-06.js hosted with ❤ by GitHub

Here you can find an JS Bin with the examples.

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