DEV Community

Discussion on: Javascript remove duplicate from array of objects

View post
Collapse
 
_genjudev profile image
Larson • • Edited

yes.
some more functions: LINK

in general a while loop is the fastest (but sometimes not, 98% of the time it will). its not recommended. Because filter is also using a while loop but also checks the values if undefined etc. It is safer to use filter. Or we need to check manually. Which would lead in a slower approach.

/* withLoop */
const found = [];
const newArray = [];

const withLoop = array => { 
  let i = 0;
  while(i < array.length) {
    if(!found.includes(array[i].id)) {
      found.push(array[i].id);
      newArray.push(array[i]);
    }
    ++i;
  }
  return newArray;
}
Enter fullscreen mode Exit fullscreen mode

The whole Set loop method it also fast, but when you need to return an array instead its slows the function down.

Thread Thread
 
peerreynders profile image
peerreynders • • Edited

in general a while loop is the fastest

Your sample code moves the temporary objects to the top level which exaggerates the difference.

but when you need to return an array instead its slows the function down.

There is no reason to store the objects in a Set in the first place so that conversion is entirely unnecessary.

One also has to keep in mind that V8 has a spread optimization which is going to penalize overuse of the spread syntax on other JavaScript engines.

Perflink

  1. withFilter
  2. withLoopSet
  3. withLoopIndexOf
  4. withLoop
  5. withSet
  6. withFor
  7. control (withFor)


Results for Chromium 96 on Ubuntu 20.04

The shape of that chart changes wildly with each run. To some degree that is to be expected as JavaScript performance is notoriously unpredictable.

Judging from the results on Firefox (94.0)

combining filter with Set doesn't help that much away from V8.