Tutorial

Object Rest and Spread in TypeScript

Published on December 9, 2016

TypeScript

Alligator.io

TypeScript 2.1 brings us object rest & spread to easily destructure, make shallow copies and merge objects into new ones.

Object Spread

Create shallow copy of objects:

const names = {cat: 'Bob', dog: 'Fred', alligator: 'Benedict'};

const newNames = { ...names };

console.log(newNames.cat); // Bob

You can merge multiple objects into a new object:

const names1 = {cat: 'Bob'};
const names2 = {dog: 'Fred', alligator: 'Benedict'};

const newNames = { ...names1, ...names2 };

console.log(newNames.alligator); // Benedict

You can add new properties too, along with using a spread:

const names = {cat: 'Bob', dog: 'Fred', alligator: 'Benedict'};

const newNames = { ...names, hamster: 'Jude' };

console.log(newNames.hamster); // Jude

Note that if a property ends up being inserted multiple times, the last one in wins:

const names = {cat: 'Bob', dog: 'Fred', alligator: 'Benedict'};

const newNames = { dog: 'Skip', ...names };

console.log(newNames.dog); // Fred

Object Rest

Similar to what we can already do in pure JavaScript with object destructuring, rest brings us something that’s in the pipelines for ES2017:

const names = {cat: 'Bob', dog: 'Fred', alligator: 'Benedict'};

const { cat, ...otherAnimals } = names;

console.log(cat); // Bob
console.log(otherAnimals); // {dog: 'Fred', alligator: 'Benedict'}

Thanks for learning with the DigitalOcean Community. Check out our offerings for compute, storage, networking, and managed databases.

Learn more about our products

About the author(s)

See author profile

Category:

Tutorial

Tags:

TypeScript

While we believe that this content benefits our community, we have not yet thoroughly reviewed it. If you have any suggestions for improvements, please let us know by clicking the “report an issue“ button at the bottom of the tutorial.