Javascript filter array by data from another

Question

I have an array object:

[
    { id:1, name: \'Pedro\'},
    { id:2, name: \'Miko\'},
    { id:3, name: \'Bear\'},
    { id:4, name: \'Teddy\'},
    { id:5, n         


        

Answer 1

Using filter and indexOf will do the trick:

var filteredArray = dataArray.filter(function(obj) {
  return idsArray.indexOf(obj.id) > -1;
});

However, indexOf has linear performance, and it will be called lots of times.

In ES6 you can use a set instead, whose has call has sublinear performance (on average):

var idsSet = new Set(idsArray),
    filteredArray = dataArray.filter(obj => idsSet.has(obj.id));

Assuming the toString method of your ids is injective, you can achieve something similar in ES5:

var idsHash = Object.create(null);
idsArray.forEach(function(id) {
  idsHash[id] = true;
});
var filteredArray = dataArray.filter(function(obj) {
  return idsHash[obj.id];
});