Benchmark: JavaScript spread operator vs Object.assign performance 661

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):

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Let's break down the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Purpose**

The benchmark tests the performance of two ways to merge two objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The goal is to determine which method is faster and more efficient.

**Options Compared**

There are two options being compared:

1. **Using the spread operator**: This method uses the three-dot notation (`...`) to create a new object with properties from both sources.
2. **Using Object.assign()**: This method takes an existing object as the target and merges properties from another source object.

**Pros and Cons of Each Approach**

**Using the Spread Operator:**

Pros:

* More concise and readable syntax
* Easier to use when merging objects with a limited number of properties
* Can be more efficient, especially for large datasets, since it creates a new object and copies only the necessary properties

Cons:

* Requires JavaScript version 2015 or later (ES6+)
* May not work in older browsers that don't support the spread operator
* Can lead to memory issues if dealing with very large objects

**Using Object.assign():**

Pros:

* Widely supported across different browsers and versions
* Works with any type of object, including arrays and other primitive types
* Can be used for more complex merging scenarios, such as updating existing properties while adding new ones

Cons:

* More verbose syntax compared to the spread operator
* May not be as efficient as using the spread operator, especially for large datasets

**Library and Special JS Feature**

In this benchmark, no libraries are explicitly mentioned. However, it's worth noting that `Object.assign()` has been a part of the JavaScript standard library since ECMAScript 2015 (ES6), while the spread operator was introduced in ECMAScript 2015 as well.

No special JS features or syntax are being tested in this benchmark. Both methods use standard JavaScript constructs.

**Other Alternatives**

If you're looking for alternative methods to merge objects, consider:

1. **Object.create()**: This method creates a new object with the specified prototype and then merges properties from another source object.
2. **For...in loops**: You can use a loop to iterate over the properties of an object and assign their values to a new object.
3. **Lodash's _.merge()` function**: This is a popular utility library that provides a convenient way to merge objects, but it may add unnecessary overhead due to its additional dependencies.

These alternatives might be useful in specific scenarios or when performance is critical, but the spread operator and `Object.assign()` are generally good choices for most use cases.

Related benchmarks:

JavaScript spread operator vs Object.assign performance 661 (version: 0)

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

Created: 7 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):