Run results for: Native slice vs copy

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

Native

5.9M/s

For Loop

3.6M/s

View exact numbers

Test name	Executions per second
✓ Native	5,867,701 Ops/sec
For Loop	3,571,926 Ops/sec

Script Preparation code:

function copy (a) {
  const l = a.length
  const b = new Array(l)
  for (let i = 0; i < l; ++i) {
    b[i] = a[i]
  }
  return b
}

function copyNative (a) {
  return a.slice(0)
}

Tests:

Native
var arr = Array(100).fill('hello') var res = copyNative(arr)
For Loop
var arr = Array(100).fill('hello') var res = copy(arr)

Run results for: Native slice vs copy

Array#slice vs for loop with array preallocation

Native

For Loop