indexOn javascript Code Snippet in 2025

Creates an object from an array, using the specified key and excluding it from each value.

• Use Array.prototype.reduce() to create an object from arr.
• Use object destructuring to get the value of the given key and the associated data and add the key-value pair to the object.

const indexOn = (arr, key) =>
  arr.reduce((obj, v) => {
    const { [key]: id, ...data } = v;
    obj[id] = data;
    return obj;
  }, {});

indexOn([
  { id: 10, name: 'apple' },
  { id: 20, name: 'orange' }
], 'id');
// { '10': { name: 'apple' }, '20': { name: 'orange' } }