Run results for: map vs reduce

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36

Browser: Chrome 80

Operating system: Mac OS X 10.14.6

Device Platform: Desktop

Date tested: 4 years ago

Script Preparation code:

var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20];
var callback = x => x * 2;

Tests:

map
array.map(callback);
reduce
array.reduce((acc, x, index) => (acc[index] = callback(x), acc), [])
reduce, defined accu length
array.reduce((acc, x, index) => (acc[index] = callback(x), acc), new Array(array.length))
reduce push
array.reduce((acc, x, index) => (acc.push(callback(x)), acc), []);
reduce concat
array.reduce((acc, x) => acc.concat(callback(x)), []);