Run results for: edit map vs slice no index start

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.79 Safari/537.36

Browser: Chrome 79

Operating system: Mac OS X 10.14.5

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
map	101740.3 Ops/sec
slice	63489.2 Ops/sec

Script Preparation code:

window.arr = new Array(2000).fill({value: 'old'});
arr[0] = {value: 'toReplace'};

Tests:

map
const newArr = arr.map((item) => item.value === 'toReplace' ? {value: 'new'} : item);
slice
const editIndex = arr.findIndex(item => item.value === 'toReplace'); const newArr = [ ...arr.slice(0, editIndex), {value: 'new'}, ...arr.slice(editIndex + 1), ];