Run results for: str += vs join

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36

Browser: Chrome 88

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
str array	4214630.0 Ops/sec
str string	707716288.0 Ops/sec

Tests:

str array
var str =["hallo"]; str.push("world"); str.join("")
AخA

var str =["hallo"];
str.push("world");
str.join("")
str string
var str ="hallo"; str += " world";
var str ="hallo";
str += " world";