Run results for: reduce.concat() vs flat() vs spread ops

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:92.0) Gecko/20100101 Firefox/92.0

Browser: Firefox 92

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
reduce + Array.prototype.concat	5627234.0 Ops/sec
Array.prototype.flat	7907171.5 Ops/sec
... spread	5832759.5 Ops/sec

Script Preparation code:

var params = [[ 1, 2 ], [ "hello", true, 7 ]];
var res_concat = params.reduce((acc, val) => acc.concat(val), []);
var res_flat = params.flat();
var res_spread = params.reduce((acc, val) => [...acc, ...val], []);

console.log("Concat Result");
console.log(JSON.stringify(res_concat));
console.log();

console.log("Flat Result");
console.log(JSON.stringify(res_flat));
console.log();

console.log("Spread Result");
console.log(JSON.stringify(res_spread));

Tests:

reduce + Array.prototype.concat
var params = [[ 1, 2 ], [ "hello", true, 7 ]]; var other = params.reduce((acc, val) => acc.concat(val), []);
Array.prototype.flat
var params = [[1, 2, params], [ "hello", true, 7 ]]; var other = params.flat();
... spread
var params = [[ 1, 2 ], [ "hello", true, 7 ]]; var other = params.reduce((acc, val) => [...acc, ...val], []);

Run results for: reduce.concat() vs flat() vs spread ops

Compare array concatination reduce, spread, flat operations

reduce + Array.prototype.concat

Array.prototype.flat

... spread