Rest parameters and spread operator in Javascript (ES6)

rest_spread_es6.js

// Snippet for rest parameters and spread operator (ES6)

// Rest parameters allow you to capture and indefinite number of parameters
// passed to a function
let sum = function(...args) {
    // args is an Array with the parameters
    return args.reduce( (prev, curr) => prev + curr);
}

console.log(sum(1, 1, 1, 1, 3)) // 7

let scaleNums = function(scale, ...nums) {
  return nums.map( (n) => scale * n);
}

console.log(scaleNums(2, 3, 4, 5, 6)) // [6, 8, 10, 12]

// Spread operator lets you "spread" an array into its individual elements
var myArray = [1, 2, 3];
var mySecondArray = [...myArray, 4, 5, 6];

console.log(...myArray); // 1 2 3
console.log(mySecondArray); // [1, 2, 3, 4, 5, 6]