Benchmark: JavaScript spread operator vs Object.assign to object 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

Latest run results:

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

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**Benchmark Overview**

The provided benchmark, hosted on MeasureThat.net, compares the performance of two approaches to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The benchmark aims to determine which method is faster and more efficient.

**Test Cases**

There are two test cases:

1. **Using the spread operator**: This test case creates two sample objects, `firstObject` and `secondObject`, and then merges them into a single object using the spread operator (`...`). The resulting object is assigned to `finalObject`.
2. **Using Object.assign()**: This test case achieves the same result as the first test case but uses the `Object.assign()` method to merge the two objects.

**Options Compared**

The two options being compared are:

* Using the spread operator (`...`)
* Using `Object.assign()`

**Pros and Cons of Each Approach**

1. **Using the spread operator (`...`):**
	* Pros:
		+ Concise and readable syntax
		+ Allows for destructuring of objects
		+ Generally faster, as it avoids the overhead of function calls and object creation
	* Cons:
		+ May not be supported in older browsers or environments that don't support ES6 features
2. **Using Object.assign():**
	* Pros:
		+ Widely supported across modern browsers and environments
		+ Allows for more control over the merging process (e.g., using a custom object as the target)
	* Cons:
		+ Can be less readable than the spread operator syntax
		+ May involve additional overhead due to function call and object creation

**Library/Functionality Used**

The benchmark uses `Object.assign()` from the built-in JavaScript Object prototype. No external libraries are required.

**Special JS Feature/Syntax**

Neither of the test cases uses any special JavaScript features or syntax beyond ES6's spread operator (`...`) or `Object.assign()`. If you're familiar with these concepts, you're already up to speed!

**Other Alternatives**

If you'd like to explore alternative approaches to merging objects in JavaScript, consider:

* Using the `merge()` function from the Lodash library
* Utilizing a custom implementation of object merging using loops or recursion
* Leveraging libraries like Object-Assign (for older browsers) or the `Object.create()` method

Keep in mind that these alternatives may not offer significant performance improvements over the spread operator or `Object.assign()`, but they can provide more control and flexibility in specific use cases.

Related benchmarks:

JavaScript spread operator vs Object.assign to object performance (version: 0)

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

Created: 4 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):