Index array based on function
Creates an object from an array, using a function to map each value to a key.
- Use
Array.prototype.reduce()to create an object fromarr. - Apply
fnto each value ofarrto produce a key and add the key-value pair to the object.
const indexBy = (arr, fn) => arr.reduce((obj, v, i) => { obj[fn(v, i, arr)] = v; return obj; }, {}); indexBy([ { id: 10, name: 'apple' }, { id: 20, name: 'orange' } ], x => x.id); // { '10': { id: 10, name: 'apple' }, '20': { id: 20, name: 'orange' } }
