One of the coolest features of ES6 is the Spread Operator. The syntax looks a bit like:
let a = [4, 5, 6];
let b = [7, …a, 8];
console.log(b);
This will give us:
The spread operator replaces the concat function in ES5:
“use strict“;
var a = [4, 5, 6];
var b = [7].concat(a, [8]);
console.log(b);
This is a great little feature, but what can we do with it?
Some Uses for the Spread Operator
We can do a lot with the spread operator.
Combine Arrays
You can use the spread operator to combine arrays:
let test = () => {
let arr1 = ['foo', 'bar','baz'];
let arr2 = ['fizz', 'buzz'];
arr1.push(...arr2); // Will append the contents of arr2 to arr1
};
test(); // Runs function
Copying Arrays
We’ve used Array.prototype.slice to make copies of arrays. Now we can do that with the spread operator.
let arr = [7, 8, 9];
let arr2 = […arr];
arr2.push(10); // Will return a deep copy of the array with 10 appended to the end
//of the values
More At the MDN
You can find more uses for the spread operator at the MDN.
