Benchmark: Object spread vs Object.assign performance

Tests:

Object spread
const a = { x: 1, y: 2, z: 3 } const b = { w: 4, u: 5, t: 6 } const c = { ...a, ... b }
Object.assign
const a = { x: 1, y: 2, z: 3 } const b = { w: 4, u: 5, t: 6 } const c = Object.assign({}, a, b)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object spread
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 provided benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark is comparing two approaches to create a new object by merging two existing objects: `Object spread` (using the spread operator, `...`) and `Object.assign`.

**Options Compared**

1. **Object Spread**: This approach uses the spread operator (`...`) to merge the properties of two objects into a new object.
2. **Object.assign**: This approach uses the `Object.assign()` method to merge the properties of two objects into a new object.

**Pros and Cons of Each Approach**

**Object Spread:**
Pros:

* More concise and readable syntax
* Works with most modern JavaScript environments

Cons:

* Can be slower than `Object.assign` for very large objects, as it involves multiple property assignments
* May not work correctly in older JavaScript versions that don't support the spread operator

**Object.assign:**
Pros:

* Generally faster and more efficient than object spread
* Works with all JavaScript versions, including older ones

Cons:

* More verbose syntax
* May have issues if the source objects are very large, as it can lead to stack overflows

**Library Used**

In this benchmark, `Object.assign()` is used. This method was introduced in ECMAScript 2015 (ES6) and is now widely supported by most modern browsers and JavaScript engines.

**Special JS Feature/Syntax**

The spread operator (`...`) is being compared here. This feature was also introduced in ES6 and allows for more concise and readable object merging.

**Other Considerations**

When choosing between these two approaches, consider the trade-off between conciseness and performance. If you need to merge a large number of properties, `Object.assign` might be a better choice. However, if readability is important and you're using modern JavaScript environments, object spread might be the way to go.

**Alternative Approaches**

If you don't have access to modern JavaScript features like the spread operator or `Object.assign()`, there are alternative approaches:

1. **Loops**: You can use nested loops to merge the properties of two objects.
2. **JSON merge libraries**: There are specialized libraries, such as Lodash's `merge()` function, that can handle object merging in a more efficient and concise way.

However, these alternatives might not be suitable for production code, especially if you're working with large or complex datasets.

Related benchmarks:

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

Comparing performance of: Object spread vs Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

Object 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):