Benchmark: Object.assign mutation vs spread

Tests:

Object.assign
const obj = {a: 1}; Object.assign(obj, {b: 2});
spread
const obj = {a: 1}; const copy = {...obj, ...{b: 2}};

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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**What is tested:**

The benchmark compares two approaches to modify an object in JavaScript:

1. **`Object.assign()`**: This method takes one or more source objects and merges them into the existing target object, returning the modified object.
2. **Spread syntax (`...`)**: This syntax creates a new object by spreading ( copying) the properties of another object.

**Options compared:**

The benchmark compares the performance of these two approaches:

* `Object.assign()`
* Spread syntax (`...`)

**Pros and Cons:**

1. **`Object.assign()`**:
	* Pros:
		+ Well-supported across browsers.
		+ Easy to use.
	* Cons:
		+ Can be slower than the spread syntax, especially for large objects.
		+ Requires multiple arguments (the target object and one or more source objects).
2. **Spread syntax (`...`)**:
	* Pros:
		+ Generally faster than `Object.assign()`.
		+ More concise and expressive.
	* Cons:
		+ Not supported in older browsers (e.g., Internet Explorer 11).
		+ Requires the target object to be defined first.

**Library usage:**

There are no libraries used in this benchmark. The focus is on comparing two built-in JavaScript features.

**Special JS feature/syntax:**

The benchmark uses the spread syntax (`...`), which is a relatively modern JavaScript feature introduced in ECMAScript 2018 (ES2018).

**Other alternatives:**

If you want to test alternative approaches, you can consider the following:

1. **Lodash's `merge()`**: A popular utility library that provides a more concise way to merge objects.
2. **Array.prototype.reduce()**: Another approach to merge objects by reducing an array of key-value pairs.

Keep in mind that these alternatives might not be as efficient or expressive as the spread syntax, and may require additional dependencies or libraries.

Overall, the benchmark provides a good comparison between two widely used JavaScript features, allowing developers to make informed decisions about which approach to use in their codebases.

Related benchmarks:

Object.assign mutation vs spread (version: 0)

Comparing performance of: Object.assign vs spread

Created: 6 years ago by: Guest

Jump to the latest result

Object.assign

spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):