Run results for: String accumulation using forEach vs. map+join vs. reduce

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.105 Safari/537.36

Browser: Chrome 84

Operating system: Mac OS X 10.15.6

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
forEach	2137534.0 Ops/sec
map+join	1851201.0 Ops/sec
reduce	1427630.0 Ops/sec

Script Preparation code:

var property = "justify-content";
var value = ["space-around", "space-evenly"];

function normalizeDeclaration(property, value) {
	return property + ":" + value;
}

Tests:

forEach
var cssText = ""; value.forEach((fallbackValue) => { cssText += "" + normalizeDeclaration(property, fallbackValue); }); var result = cssText.slice(1);
map+join
var result = value .map((fallbackValue) => normalizeDeclaration(property, fallbackValue)) .join(";");
reduce
var result = value.reduce( (accumulator, fallbackValue) => accumulator + ";" + normalizeDeclaration(property, fallbackValue), normalizeDeclaration(property, value[0]) );