Benchmark: JavaScript spread operator vs Object.assign performance 3000

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):

LLMs can make mistakes. Check important info.

The provided benchmark is testing the performance of two different methods to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. Let's break down what each test case is trying to achieve, their pros and cons, and other considerations.

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

```javascript
const firstObject = { sampleData: 'Hello world' }
const secondObject = { moreData: 'foo bar' }
const finalObject = {
  ...firstObject,
  // No spread operator for secondObject as it's not needed
}
```

In this test case, we're using the spread operator (`...`) to merge two objects: `firstObject` and an empty object. The spread operator is called when you use the syntax `const finalObject = { ...firstObject }`. This creates a shallow copy of `firstObject`, preserving all its key-value pairs.

Pros:

* More concise and readable code
* Supports nested objects

Cons:

* Only works for shallow merge (i.e., doesn't handle nested properties)
* Can be less efficient than other methods, especially for large datasets

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

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

In this test case, we're using `Object.assign()` to merge two objects. The `Object.assign()` method returns a new object that is a shallow copy of the source array.

Pros:

* Works for both shallow and deep merge (i.e., handles nested properties)
* More flexible than the spread operator

Cons:

* Less concise and more verbose code
* Can be less efficient than other methods, especially for large datasets

**Library/Functionality Used**

`Object.assign()` is a built-in JavaScript method that merges multiple source objects into one object.

**Special JS Feature/Syntax**

None mentioned in this benchmark. However, if you're interested in learning about some special features or syntax, I can cover them separately!

**Other Alternatives**

1. **Merge Object**: A utility function that merges two objects recursively.
```javascript
function mergeObjects(obj1, obj2) {
  return { ...obj1, ...obj2 }
}
```

2. **Lodash's _.assign()**: A popular utility library for functional programming in JavaScript.
```javascript
import _ from 'lodash';
const finalObject = _.assign({}, firstObject, secondObject);
```

3. **ES6 Spread Syntax with Rest Parameters**: While not exactly a merge function, you can use the spread syntax (`{ ...obj1, ...obj2 }`) to create a new object and pass it to a function that expects multiple arguments.
```javascript
function mergeObjects(obj1, obj2) {
  return (...args) => ({ ...args[0], ...args[1] });
}

const finalObject = mergeObjects(firstObject, secondObject);
```

Keep in mind that these alternatives might have different performance characteristics and use cases compared to the original `Object.assign()` method.

Related benchmarks:

JavaScript spread operator vs Object.assign performance 3000 (version: 0)

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

Created: 2 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):