Run results for: Lodash uniqBy vs Set vs custom uniqBy

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/117.0

Browser: Firefox 117

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 9 months ago

Test name	Executions per second
Lodash uniqBy	971139.9 Ops/sec
Set	798495.4 Ops/sec
custom uniqBy	492697.5 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 MyArr = Array.from({length: 40}, () => Math.floor(Math.random() * 40));

var myCopy = null;

function uniqBy(arr, predicate) {
  const cb = typeof predicate === 'function' ? predicate : (o) => o[predicate];
  
  return [...arr.reduce((map, item) => {
    const key = (item === null || item === undefined) ? 
      item : cb(item);
    
    map.has(key) || map.set(key, item);
    
    return map;
  }, new Map()).values()];
};

Tests:

Lodash uniqBy
myCopy = _.uniqBy(MyArr);
Set
myCopy = [...new Set(MyArr)]
custom uniqBy
myCopy = uniqBy(MyArr, v => v)