Run results for: lodash groupBy vs Array.reduce 100k fair

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser: Chrome 97

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Lodash	276.9 Ops/sec
Native	367.8 Ops/sec
groupByReduce	140.4 Ops/sec
groupByReduceBetter	377.2 Ops/sec
groupByHasOwnProperty	359.5 Ops/sec
groupByMapBetter	139.9 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 = 100000;

var data = [];
for (var i = 0; i <= max2; i++) { data.push({ id: i }); }





function groupByReduce(arr, iteratee) {
    return arr.reduce((acc, v) => {
      const k = iteratee(v);
      (acc[k] || (acc[k] = [])).push(v)
      return acc;
  }, {})
}

function groupByReduceBetter(arr, iteratee) {
    return arr.reduce((acc, v) => {
      const k = iteratee(v);
      if(acc[k]) {
        acc[k].push(v);
      } else {
        acc[k] = [v];
      }
      return acc;
  }, {})
}

function groupByHasOwnProperty(arr, iteratee) {
    return arr.reduce((acc, v) => {
      const k = iteratee(v);
      if(acc.hasOwnProperty(k)) {
        acc[k].push(v);
      } else {
        acc[k] = [v];
      }
      return acc;
  }, {})
}


function groupByMap(arr, iteratee) {
  const m = new Map();

  for (const v of arr) {
      const k = iteratee(v);
      const temp = m.get(k) ?? [];
      temp.push(v);
      m.set(k, temp)
  }
  return m;
}

function groupByMapBetter(arr, iteratee) {
  const m = new Map();

  for (let length = arr.length, i = 0; i < length; ++i) {
      const k = iteratee(arr[i]);
      let temp = m.get(k);
      if (temp) {
        temp.push(arr[i]);
      } else {
        temp = [arr[i]]
      }
      m.set(k, temp)
  }
  return m;
}

var iteratee = ({ id }) => id

Tests:

Lodash
_.groupBy(data, iteratee)
Native
data.reduce((acc, item) => { if(acc[item.id]) { acc[item.id].push(item); } else { acc[item.id] = [item]; } return acc; }, {})
groupByReduce
groupByReduce(data, iteratee)
groupByReduceBetter
groupByReduceBetter(data, iteratee)
groupByHasOwnProperty
groupByHasOwnProperty(data, iteratee)
groupByMapBetter
groupByMapBetter(data, iteratee)

Run results for: lodash groupBy vs Array.reduce 100k fair

Lodash

Native

groupByReduce

groupByReduceBetter

groupByHasOwnProperty

groupByMapBetter