30-seconds-of-code/snippets/mapObject.md

title, tags

title	tags
mapObject	array,object,advanced

Maps the values of an array to an object using a function, where the key-value pairs consist of the stringified value as the key and the mapped value.

Use Array.prototype.map() to convert each element in arr to an Object literal with one property. Use el as the property's name (el.toString() will be called internally), and call the passed fn with el to derive the property's value. Use the spread operator (...) to call Object.assign() with the elements of the mapped array.

const mapObject = (arr, fn) => Object.assign(...arr.map(el => ({ [el]: fn(el) })));

const squareIt = arr => mapObject(arr, a => a * a);
squareIt([1, 2, 3]); // { 1: 1, 2: 4, 3: 9 }