Benchmark: JavaScript spread operator vs Object.assign performance123

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);
Using Object.assign2
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(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
Using Object.assign2

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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Let's break down what's being tested in the provided benchmark.

**What is being tested?**

The benchmark is testing the performance of three different approaches to merge two objects into one:

1. Using the spread operator (`...`)
2. Using `Object.assign()`
3. Using a nested call to `Object.assign()` (i.e., `Object.assign(Object.assign(firstObject), secondObject)`)

**Options being compared**

The benchmark is comparing the performance of these three approaches on two objects with different data: `firstObject` and `secondObject`. The objects are defined as:
```javascript
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
```
**Pros and Cons of each approach**

1. **Using the spread operator (`...`)**
	* Pros:
		+ Concise and readable syntax
		+ No need to define a separate function or method for merging objects
	* Cons:
		+ Might be slower due to the creation of a new array with object properties
2. **Using `Object.assign()`**
	* Pros:
		+ Widely supported and used in the industry
		+ Can be combined with other methods (e.g., `Array.prototype.push()`) for more complex merging scenarios
	* Cons:
		+ Might require additional code to handle edge cases or errors
3. **Using a nested call to `Object.assign()`**
	* Pros:
		+ Might be faster due to the creation of an array with object properties (less overhead than creating a new object)
	* Cons:
		+ More verbose and less readable syntax
		+ Requires additional nesting, which can make error-prone

**Library used**

None in this specific benchmark. However, it's worth noting that `Object.assign()` is a built-in method in JavaScript, so no library is required.

**Special JS feature or syntax**

No special features or syntax are being tested in this benchmark.

**Other alternatives**

For merging objects, other alternatives include:

1. **Using the `...` spread operator with an object initializer**: e.g., `{ ...firstObject, ...secondObject }`
2. **Using a custom merge function**: e.g., `function merge(obj1, obj2) { return Object.assign({}, obj1, obj2); }`
3. **Using a library like Lodash's `merge` function**: e.g., `_.merge(firstObject, secondObject)`

Related benchmarks:

JavaScript spread operator vs Object.assign performance123 (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign vs Using Object.assign2

Created: 3 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Using Object.assign2

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):