The destructuring assignment syntax is a JavaScript expression that makes it possible to extract data from arrays or objects into distinct variables.

es6_destructuring_assignment.js

var a, b, rest;
[a,b] = [1,2];
console.log(a); // 1
console.log(b); // 2  // wow, so convenient!  will I remember to do this, or not bother?

[a, b, ...rest] = [1, 2, 3, 4, 5];
console.log(a); // 1
console.log(b); // 2
console.log(rest); // [3, 4, 5]  // incredible... although now I'm thinking this is nearly illegible for other developers

({a, b} = {a:1, b:2})
console.log(a); // 1
console.log(b); // 2

({a, b, ...rest} = {a:1, b:2, c:3, d:4}); //ES7 - not implemented in Firefox 47a01


var x = [1, 2, 3, 4, 5];
var [y, z] = x;
console.log(y); // 1
console.log(z); // 2