const suite = new (require("benchmark")).Suite;

let a, b;

const reset = () => { a = [1,2,3]; b = [4,5,6] }

suite.add("Concat", function() {
    reset();

    a = a.concat(b);
}).add("Push.apply", function() {
    reset();

    [].push.apply(a, b);
}).add("Spread operator", function() {
    reset();

    a = [...a, ...b];
}).on("cycle", function(event) {
    console.log(String(event.target));
}).on("complete", function() {
    console.log("Fastest is " + this.filter("fastest").map("name"));
}).run({ async: true });