Run results for: Array.prototype.concat vs spread operator - merging two Objects Arrays (Updated Oct 2020)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.0 Safari/605.1.15

Browser: Safari 14

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Array.prototype.concat	6621629.0 Ops/sec
spread operator (spread at head)	10978520.0 Ops/sec
spread operator x2 (head and tail)	9088666.0 Ops/sec

Tests:

Array.prototype.concat
const response = [ { 'hundo': 100 }, { 'nine': 9 }, {'nested': { 'twos': 22 }} ]; const state = [ { 'ten': 10 }, { 'six': 6 }, {'nested': { 'five': 5 }} ].concat(response);
spread operator (spread at head)
const response = [ { 'hundo': 100 }, { 'nine': 9 }, {'nested': { 'twos': 22 }} ]; const state = [ ...response, { 'ten': 10 }, { 'six': 6 }, {'nested': { 'five': 5 }} ];
spread operator x2 (head and tail)
const prevState = [ { 'ten': 10 }, { 'six': 6 }, {'nested': { 'five': 5 }} ]; const newItems = [ { 'hundo': 100 }, { 'nine': 9 }, {'nested': { 'twos': 22 }} ]; const state = [ ...prevState, ...newItems ];