Five users for the Spread Operator in JavaScript

5 Uses for the Spread Operator

Copy array

let arr = [1,2,3,4]
let copy = [...arr]
// copy is [ 1, 2, 3, 4 ]

Concatenate arrays

let arr1 = [1,2,3,4]
let arr2 = [5,6,7,8]
let concat = [...arr1, ...arr2]
// concat is [ 1, 2, 3, 4, 5, 6, 7, 8 ]

Pass arguments as arrays

function dev(x, y, z) { }
var args = [0, 1, 2]
dev(...args) // call function

Copy Object

let obj = {a: 1, b: 2, c: 3}
let copy = {...obj}
// obj is {a: 1, b: 2, c: 3}

Merge Object

let obj1 = {a: 1, b: 2, c: 3}
let obj1 = {d: 4, e: 5, f: 6}
let merge = {...obj1, ...obj2}
// merge is {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6}

Find more details on the source link above, thanks to @laurie for putting this list together https://dev.to/laurieontech