Benchmark: Spread vs Object.assign ref

Tests:

Spread
let firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } firstObject = { ...firstObject, ...secondObject };
Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } Object.assign(firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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I'll break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is defined by two test cases: `Spread` and `Object.assign`. The script preparation code for both tests is empty, indicating that no specific setup or initialization is required before running the benchmarks.

**Test Cases**

### Spread

This test case measures the performance of the spread operator (`...`) in JavaScript. The benchmark definition includes a sample data structure:
```javascript
let firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
firstObject = {
  ...firstObject,
  ...secondObject
}
```
The test case is trying to create a new object by merging `firstObject` and `secondObject` using the spread operator. The benchmark likely measures how many times this operation can be performed in one second, which indicates the performance of the JavaScript engine.

Pros:

* Simplistic syntax: Using the spread operator makes the code more readable and concise.
* Efficient: The spread operator is optimized by most modern JavaScript engines for its performance.

Cons:

* Limited support: Older browsers might not support the spread operator or may have limited support, which could affect benchmark results.
* Potential overhead: Depending on the specific use case, there might be a small performance hit due to the creation of intermediate objects.

### Object.assign

This test case measures the performance of the `Object.assign` method in JavaScript. The benchmark definition includes:
```javascript
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }

// Using Object.assign to merge two objects
Object.assign(firstObject, secondObject)
```
The test case is trying to merge `firstObject` and `secondObject` using the `Object.assign` method. The benchmark likely measures how many times this operation can be performed in one second.

Pros:

* Wide support: Most modern browsers and JavaScript engines support `Object.assign`.
* Efficient: `Object.assign` is optimized for performance, especially when used with arrays or other iterable objects.

Cons:

* Less concise syntax: Compared to the spread operator, using `Object.assign` requires more code.
* Potential overhead: Depending on the specific use case, there might be a small performance hit due to the method call and object creation.

**Other Considerations**

If test users are familiar with modern JavaScript features, they should note that both tests rely on features that have been around for a while. These features are:

* The spread operator (`...`)

The tests do not use any special JavaScript features or syntax that might affect the benchmark results.

**Alternatives**

If you're looking for alternative approaches to merge two objects in JavaScript, consider using the following methods:

1. `for...in`: Iterating over object properties and assigning values using a loop.
2. `Object.create()`: Creating a new object and then assigning properties from another object using `Object.assign()` or `Object.prototype.assign()`.
3. Using libraries like Lodash's `merge` function, which provides a more concise and readable way to merge objects.

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

Related benchmarks:

Spread vs Object.assign ref (version: 0)

Comparing performance of: Spread vs Object.assign

Created: 6 years ago by: Guest

Jump to the latest result

Spread

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):