Benchmark: JavaScript spread operator vs Object.assign performance23454234

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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Let's break down the benchmark and its test cases.

**Benchmark Overview**

The benchmark measures the performance of two approaches to merge objects in JavaScript:

1. Using the spread operator (`...` syntax)
2. Using `Object.assign()`

**Test Case 1: Using the Spread Operator**

The test case uses a simple example where three objects are merged together:

```javascript
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = {
  ...firstObject,
  ...secondObject
}
```

In this approach, the spread operator (`...`) is used to merge two objects into a new object. The resulting object contains all properties from both `firstObject` and `secondObject`, without any duplication.

**Test Case 2: Using Object.assign()**

The second test case uses an identical example:

```javascript
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = Object.assign({}, firstObject, secondObject)
```

Here, the `Object.assign()` method is used to merge two objects into a new object. The resulting object contains all properties from both `firstObject` and `secondObject`, without any duplication.

**Comparison of Options**

The two approaches have different performance characteristics:

* **Using Spread Operator:**
	+ Pros:
		- Readability: More concise and expressive syntax.
		- Performance: Generally faster, as it avoids the overhead of function calls and object creation.
	+ Cons:
		- Browser Support: Older browsers (pre-ES6) may not support the spread operator.
		- Compatibility: Some older JavaScript environments may not have optimized implementations for the spread operator.
* **Using Object.assign():**
	+ Pros:
		- Wide Browser Support: Works in all modern browsers, including older versions of Internet Explorer.
		- Consistency: The `Object.assign()` method is a standardized part of the JavaScript language.
	+ Cons:
		- Readability: Less concise syntax, which may make it harder to read for some developers.

**Other Considerations**

* **Library Usage:** Neither test case uses any external libraries. However, if you were to add additional functionality or dependencies, this could impact performance and benchmarking results.
* **JS Features/Syntax:** There are no special JavaScript features or syntax used in these benchmarks. The focus is on comparing two standard approaches.

**Alternatives**

If you need to compare other merge approaches, here are some alternatives:

* Using `reduce()`: You can use the `reduce()` method to accumulate objects:
```javascript
const finalObject = Object.values(firstObject).reduce((acc, val) => ({ ...acc, [key]: val }), {})
```
* Using a library like Lodash's `merge()`: This library provides an optimized implementation for merging objects.
```javascript
import _ from 'lodash';
const finalObject = _.merge({}, firstObject, secondObject);
```

Keep in mind that these alternatives may have different performance characteristics and implications for your specific use case.

Related benchmarks:

JavaScript spread operator vs Object.assign performance23454234 (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):