Run results for: lodash groupBy vs Array.reduce(3 ways) 10k

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:96.0) Gecko/20100101 Firefox/96.0

Browser: Firefox 96

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Lodash	7637.2 Ops/sec
Native reduce	6612.2 Ops/sec
Native reduce (ownProperty check)	8403.0 Ops/sec
Native reduce (only if)	4076.9 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:

var max2 = 10000;

var data = [];
for (var i = 0; i <= max2; i++) { data.push({ id: i, title: `a${i}bc` }); }

function whileGroup(data) {
  const grouped = {};
  const length = data.length;
  let i = 0;

  while(i < length) {
    const item = data[i];
    if(grouped[item.id]) grouped[item.id].push(item);
    else grouped[item.id] = [];
    
    i++;
  } 
  
  return grouped;
}

Tests:

Lodash
_.groupBy(data, ({ id }) => id)
Native reduce
data.reduce((acc, item) => { if(acc[item.id]) acc[item.id].push(item); else acc[item.id] = [item]; return acc; }, {})
Native reduce (ownProperty check)
data.reduce((acc, item) => { if({}.hasOwnProperty.call(acc, "id")) acc[item.id].push(item); else acc[item.id] = [item]; return acc; }, {})
Native reduce (only if)
data.reduce((acc, item) => { if(!acc[item.id]) acc[item.id] = []; acc[item.id].push(item); return acc; }, {})

Run results for: lodash groupBy vs Array.reduce(3 ways) 10k

Lodash

Native reduce

Native reduce (ownProperty check)

Native reduce (only if)