Benchmark: JavaScript spread operator vs Object.assign with {} performance

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

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

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Let's break down the benchmark and its components.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares the performance of two approaches:

1. Using the spread operator (`...`) to merge two objects into a new object.
2. Using `Object.assign()` with an empty object (`{}`) to merge two objects into a new object.

**Options compared:**

The benchmark tests the performance of these two approaches in creating a new object by merging two existing objects. The options are:

1. **Spread operator (`...`)**: This is a modern JavaScript feature introduced in ES6 that allows you to spread the properties of an object onto a new object using the `...` syntax.
2. **Object.assign() with `{}`**: This method copies the specified values to each property of the target object.

**Pros and cons of each approach:**

1. **Spread operator (`...`)**:
	* Pros:
		+ More concise and readable code
		+ Less prone to errors due to explicit merging of properties
	* Cons:
		+ May not be supported in older browsers or environments
		+ Can be slower due to the need for the JavaScript engine to create a new object and merge properties
2. **Object.assign() with `{}`**:
	* Pros:
		+ Widely supported across modern browsers and environments
		+ Faster execution since it only creates an empty object and copies values into it
	* Cons:
		+ Can be less readable due to the explicit use of `Object.assign()` and an empty object

**Library usage:**

There is no specific library used in this benchmark. The test cases rely on built-in JavaScript features.

**Special JS feature or syntax:**

The spread operator (`...`) introduced in ES6 is a special JavaScript feature that allows you to spread the properties of an object onto a new object. This feature was not available in older versions of JavaScript, making it a more modern approach.

**Other alternatives:**

If you wanted to test other approaches for merging objects, some possible alternatives could be:

* Using the `Object.create()` method and assigning values to it
* Using a library like Lodash's `merge` function
* Using a custom implementation with manual property assignment

Keep in mind that these alternatives might have different performance characteristics or requirements compared to the spread operator and `Object.assign()`.

Related benchmarks:

JavaScript spread operator vs Object.assign with {} performance (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 6 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

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):