How can I replace array item with matched object keys?

August 24, 2022

Let’s say I have an array of id’s
const ids = [[1, 2, 3], [2, 3], [3]]

And have array with objects that have name for each id

const obj = [
    { id: 1, name: "One" },
    { id: 2, name: "Two" },
    { id: 3, name: "Three" },
  ];

What is the most proper way to get ids = [["One", "Two", "Three"], ["Two", "Three"], ["Three"]], I’m worrying that nested mapping could cause performance issues.

>Solution :

Use a combination of map and find. There may be a more performant way of doing it, but I’d suggest worrying about that only if you run into performance issues :-

const ids = [[1, 2, 3], [2, 3], [3]];

const obj = [
    { id: 1, name: "One" },
    { id: 2, name: "Two" },
    { id: 3, name: "Three" },
  ];

const mapped = ids.map(arr => arr.map(id => obj.find(obj => obj.id === id).name));