Run results for: arguments join vs string concatenate

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Browser: Chrome 67

Operating system: Mac OS X 10.13.3

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
join	1392115.4 Ops/sec
concat	4337927.5 Ops/sec
concatSep	2745338.0 Ops/sec
concatSepSubstr	2756846.5 Ops/sec

Script Preparation code:

function join() {
	return Array.prototype.join.call( arguments );
}
function concat() {
	var result = '';
	for ( var i = 0, il = arguments.length; i < il; i++ ) {
		result += arguments[ i ];
	}
	return result;
}
function concatSep() {
	var result = '';
	for ( var i = 0, il = arguments.length; i < il; i++ ) {
		result += arguments[ i ] + ',';
	}
	return result;
}
function concatSepSubstr() {
	var result = '';
	for ( var i = 0, il = arguments.length; i < il; i++ ) {
		result += arguments[ i ] + ',';
	}
	return result.slice( 0, -1 );
}

Tests:

join
join( 1, 2, '3', {}, true, null );
concat
concat( 1, 2, '3', {}, true, null );
concatSep
concatSep( 1, 2, '3', {}, true, null );
concatSepSubstr
concatSepSubstr( 1, 2, '3', {}, true, null );