Fastest Array Joins on Strings

array_joining.js

var array = ['livechat', 'visitors', 'apple', 'display_name'];

function testConcat(y) {
	return array.concat([y]);
}

function testDeconstruct(y) {
	return [...array, y];
}

function testBabel(y) {
	return [].concat(_toConsumableArray(array), [y]);
}

function testSplice(y) {
	return array.concat().splice(array.length, 0, y);
}

function testPush(y) {
	var a = array.concat();
	a.push(y);
	return a;
}

function testMakeNew(y) {
	var a = new Array(array.length);
	for (var i =0; i < array.length; i++) {
		a.push(array[i]);
	}
	a.push(y);
	return a;
}

function join2(array, y) {
	var a = new Array(array.length + 1);
	for (var i =0; i < a.length; i++) {
		a[i] = (array[i]);
	}
	a[a.length - 1] = y;
	return a;
}

function testMakeNew2(y) {
	join2(array, y);
}


function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

var many = ['ali', 'banana', 'somewan', 'poot', 'yli'];

var iterations = 100000;

console.time('concat');
for (var i = 0; i < iterations; i++) many.forEach(testConcat);
console.timeEnd('concat');

console.time('deconstruct');
for (var i = 0; i < iterations; i++) many.forEach(testDeconstruct);
console.timeEnd('deconstruct');

console.time('deconstruct2');
for (var i = 0; i < iterations; i++) many.forEach(testBabel);
console.timeEnd('deconstruct2');

console.time('deconstruct3');
for (var i = 0; i < iterations; i++) many.forEach(testSplice);
console.timeEnd('deconstruct3');

console.time('deconstruct4');
for (var i = 0; i < iterations; i++) many.forEach(testPush);
console.timeEnd('deconstruct4');

console.time('deconstruct5');
for (var i = 0; i < iterations; i++) many.forEach(testMakeNew);
console.timeEnd('deconstruct5');

console.time('deconstruct6');
for (var i = 0; i < iterations; i++) many.forEach(testMakeNew2);
console.timeEnd('deconstruct6');

results

node array_joining

concat: 192.467ms
deconstruct: 243.186ms
deconstruct2: 279.228ms
deconstruct3: 217.192ms
deconstruct4: 140.693ms
deconstruct5: 43.969ms
deconstruct6: 37.521ms