Quick benchmark of various iteration styles

iteration.js

'use strict'

const tests = [
  test(testFor),
  test(testForAlt),
  test(testForEach),
  test(testReduceFunction),
  test(testReduceArrows),
  test(testForOf)
]
console.log(tests.length)

/**
 * Test Cases
 */

function testFor (items) {
  let result = 0
  for (let i = 0; i < items.length; i++) {
    result += items[i]
  }
  return result
}

function testForAlt (tokens) {
  let result = 0
  for (let i = 0, token; (token = tokens[i]); i++) {
    const token = tokens[i]
    result += token
  }
  return result
}

function testForEach (items) {
  let result = 0
  items.forEach((item) => {
    result += item
  })
  return result
}

function testReduceArrows (items) {
  return items.reduce((c, item) => c += item)
}

function testReduceFunction (items) {
  return items.reduce(function (c, item) {
    return c += item
  })
}

function testForOf (items) {
  let result = 0
  for (let item of items) {
    result += item
  }
  return result
}

/**
 * Fixture generator
 */

function generate (size = 10000000) {
  const items = []
  for (let i = 0; i < size; i++) {
    items.push(Math.random())
  }
  return items
}

/**
 * Test Runner
 */

function test (testFn) {
  const items = generate()
  const name = testFn.name.replace('test', '')
  console.time(name)
  const result = testFn(items)
  console.timeEnd(name)
  return result
}

results.txt

For: 186.791ms
ForAlt: 270.132ms
ForEach: 458.686ms
ReduceFunction: 321.777ms
ReduceArrows: 334.990ms
ForOf: 1565.900ms