Run results for: Concatenation vs substring

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:87.0) Gecko/20100101 Firefox/87.0

Browser: Firefox 87

Operating system: Ubuntu

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Concat	121.3 Ops/sec
Find & Substring	195.2 Ops/sec

Script Preparation code:

var string = "HelloWorld!".repeat(100) + " Hi";

Tests:

Concat
for (let i = 0; i < 200; ++i) { let result = ''; for (let j = 0; j < string.length; ++j) { if (' ' === string[j]) { break; } result += string[j]; } }
Find & Substring
for (let i = 0; i < 200; ++i) { let j; for (j = 0; j < string.length; ++j) { if (' ' === string[j]) { break; } } let result = string.substring(0, j); }