Run results for: reduce variants

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.125 Safari/537.36

Browser: Chrome 84

Operating system: Mac OS X 10.15.6

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
for...of	7006.0 Ops/sec
reduce spread	5.2 Ops/sec
reduce mutate	1875.5 Ops/sec
object.fromEntries ...map	1249.2 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

function getItems(count) {
  let id = 1;
  return _.times(count, () => ({
    name: "city" + id++,
    visited: true
  }))
}

var items = getItems(1000)

Tests:

for...of
const result = {}; for(let item of items) { result[item.name] = item.visited; }
reduce spread
let initial = {}; const result = items.reduce((accumulator, item) => ({ ...accumulator, [item.name]: item.visited }), initial);
reduce mutate
let initial = {}; const result = items.reduce((accumulator, item) => { accumulator[item.name] = item.visited; return accumulator; }, initial);
object.fromEntries ...map
let result = Object.fromEntries( items.map(({ name, visited }) => [name, visited]) );

Run results for: reduce variants

Adapted from https://gist.github.com/snapwich/7604b2d827f320e470a07e088e0293f3

for...of

reduce spread

reduce mutate

object.fromEntries ...map