Benchmark: Object.assign vs spread operator.

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var other = Object.assign({ a: 2 }, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var other = { a: 2, ...params };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator

Fastest: N/A

Slowest: N/A

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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Let's dive into the details of this benchmark.

**What is being tested?**

The benchmark is comparing two ways to merge objects in JavaScript:

1. **Object.assign**: A method that takes multiple arrays or objects as arguments and returns a new object with all properties from each source object.
2. **Spread operator (ES6)**: An operator (`{ ...obj }`) that creates a shallow copy of an object, where `obj` is the source object.

**What options are compared?**

In this benchmark, two test cases are run:

1. **Object.assign**: A script uses the `Object.assign()` method to merge a predefined object (`params`) with another object containing only one property (`a: 2`). The resulting merged object is assigned to the variable `other`.
```javascript
var params = { b:"hello", c: true, d:7 };
var other = Object.assign({ a: 2 }, params);
```
2. **Spread operator**: A script uses the spread operator (`{ ...params }`) to create a new object that includes all properties from the `params` object, along with an additional property (`a: 2`). The resulting merged object is assigned to the variable `other`.
```javascript
var params = { b:"hello", c: true, d:7 };
var other = { a: 2, ...params };
```
**Pros and Cons of each approach**

Both methods achieve the same result (merging objects), but with some differences:

* **Object.assign**: This method is more traditional and widely supported across different browsers. It's also relatively fast.
* **Spread operator**: This method is a newer feature in JavaScript (introduced in ES6) and provides a more concise way to merge objects. However, it might be slower than `Object.assign` due to the overhead of creating a new object.

**Other considerations**

When choosing between these methods, consider:

* **Compatibility**: If you need to support older browsers or environments that don't have the spread operator, use `Object.assign`.
* **Readability**: If your code is meant for human readers, the spread operator can make the intent of merging objects clearer and more concise.
* **Performance**: For large datasets or performance-critical applications, `Object.assign` might be a better choice due to its faster execution time.

**Libraries and special JS features**

In this benchmark, no external libraries are used. The test cases only utilize built-in JavaScript methods and syntax (specifically, the spread operator).

**Alternative approaches**

Other ways to merge objects in JavaScript include:

* **Lodash's merge**: A utility function that merges multiple objects into one.
* **Object.assign with a custom merge function**: You can create your own merge function using `Object.assign` as a starting point.

These alternatives might offer additional features, such as handling nested objects or merging arrays, but are not used in this specific benchmark.

Related benchmarks:

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

Comparing performance of: Object.assign vs spread operator

Created: 6 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):