A Comprehensive Comparison: Spread Syntax vs. Object.assign() in JavaScript

Delve into the pros and cons of using either method for cloning and merging objects in JavaScript

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Cloning and merging objects are frequent tasks in modern web development. Since ES6, JavaScript provides several options for achieving these goals. Specifically, the spread syntax (...) and the Object.assign() method often come under discussion regarding performance, ease of use, and compatibility.

This article aims to clarify the distinctions between the two techniques and offer guidance on choosing the best approach depending on specific project requirements.

Syntax Overview

Spread Syntax

Introduced in ES6, the spread syntax offers a convenient way to clone and merge objects. Its compactness makes it highly appealing for many developers who favor brevity and readability. Let’s take a quick look at an example below:

const original = { a: 1, b: 2 };
const copy = { ...original };
console.log(copy); // Output: { a: 1, b: 2 }

Using the spread syntax, we successfully created a shallow copy of the original object. Now, if we modify the copied version, the original remains unaffected: