Merge Object Properties with the Spread Operator

Last week I wrote 6 Great Uses of the Spread Operator, a post detailing how awesome the spread operator (...) is for working with arrays and other iterable objects.  As always my readers chimed in with a few other great uses and which you should check out in the comments.  And of course as soon as I publish the post I find another great use of the spread operator while I tinker with Babel and React:  merging multiple objects’ properties into one object!

The JavaScript

Wrap any objects you’d like merged into one with braces ({}):

const person = { name: 'David Walsh', gender: 'Male' };
const tools = { computer: 'Mac', editor: 'Atom' }; const summary = {...person, ...tools};
/*
Object { "computer": "Mac", "editor": "Atom", "gender": "Male", "name": "David Walsh",
}
*/

A new object is created containing all properties and values from the objects provided with the rest operator.  Also note that you can provide any number of objects to merge:

const person = { name: 'David Walsh', gender: 'Male' };
const tools = { computer: 'Mac', editor: 'Atom' };
const attributes = { handsomeness: 'Extreme', hair: 'Brown', eyes: 'Blue' }; const summary = {...person, ...tools, ...attributes};
/*
Object { "computer": "Mac", "editor": "Atom", "eyes": "Blue", "gender": "Male", "hair": "Brown", "handsomeness": "Extreme", "name": "David Walsh",
}
*/

I love how easy merging objects is using the spread operator.  You can use Object.assign to accomplish the same feat but the spread operator makes things a bit shorter if you don’t mind a slightly less descriptive syntax!

Note:  This syntax is not yet support by all browsers but you can use Babel with the transform-object-rest-spread plugin to enable object merging with the spread operator.

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