Other Cool

Some features of ES6…

While there are many features that are coming out in ES6 and ES7. There are few ones that are pretty easy to wrap your head around.

Let Operator
Using let operator instead of var operator you can define variable whose scope is defined inside any block scope, any curly brackets.

function a() {

  for (var i =0; i < 10; i++) {
    var b = i+1;
    let c = i;
  }
  console.log(b); //will have a value
  console.log(c); //undefined error
}

One of the limits are that let variables can’t be redefined.

let a = 3;
let a = 5; //wrong.. error.

Const

const is like const in any other programming languages, it’s used to defined constants, variables which are defined and assigned once can’t be redefined or reassigned.

In ES6, you have to assign value to const, whenever you declare it.
const is also block scoped, just like let. var is function scoped.

const PI = 3.14;
PI = 3.15; // gives error
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