Run results for: Immer vs Spread Reducer With Filled State (replace with diff key and value)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser: Chrome 125

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

Mutate

7.2M/s

immer pull up

2.0M/s

Spread

712K/s

immer

2K/s

View exact numbers

Test name	Executions per second
✓ Mutate	7,199,329 Ops/sec
immer pull up	2,013,295 Ops/sec
Spread	711,904 Ops/sec
immer	1,910 Ops/sec

HTML Preparation code:

<script src="https://cdn.jsdelivr.net/npm/immer@3.1.3/dist/immer.umd.min.js"></script>
<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
  }))
}


data = getItems(1000).reduce((acc, curr) => ({ ...acc, [curr.name]: curr.visited }), {})
action = { name: 'city1', visited: false };

Tests:

immer
const reducer = (state, curr) => { return immer.produce(state, draft => { draft[curr.name] = curr.visited }) }; reducer(data, action)
Mutate
const reducer = (draft, curr) => { draft[curr.name] = curr.visited; return draft; }; reducer(data, action)
Spread
const reducer = (draft, curr) => ({ ...draft, [curr.name]: curr.visited }); reducer(data, action)
immer pull up
const reducer = immer.produce((draft, curr) => { draft[curr.name] = curr.visited; }); reducer(data, action)