Benchmark: Javascript Spread vs Object.Assign (to {})

Tests:

Spread
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
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
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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**Benchmark Explanation**

The provided benchmark compares two approaches for merging objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The test case uses an object, `firstObject`, with some data, and another object, `secondObject`, with more data. The goal is to create a new object, `finalObject`, by combining these two objects.

**Options Compared**

The benchmark compares the performance of two approaches:

1. **Spread Operator (`...`)**: This approach uses the spread operator to merge the two objects. It takes advantage of the fact that when you use the spread operator with an object literal, it creates a new array-like object containing all the key-value pairs from both objects.
2. **Object.assign()**: This approach uses the `Object.assign()` method to copy properties from one or more source objects to a target object.

**Pros and Cons**

**Spread Operator (`...`)**

Pros:

* More concise and readable code
* Creates a new object with all the key-value pairs, which can be faster than copying individual properties
* Supports nested objects and arrays

Cons:

* Can be slower due to the creation of an intermediate array-like object
* May not work as expected in certain situations, such as when dealing with functions or other types of values

**Object.assign()**

Pros:

* More efficient for simple property copies, especially when copying individual properties
* Works well with functions and other types of values that cannot be spread

Cons:

* Can result in slower performance due to the overhead of calling `Object.assign()` method
* May not work as expected when dealing with nested objects or arrays

**Other Considerations**

When choosing between these approaches, consider the following factors:

* Code readability: If readability is a top priority, using the spread operator might be a better choice.
* Performance: If performance is critical, using `Object.assign()` might be a better choice for simple property copies.
* Complexity: When dealing with complex objects or nested structures, the spread operator might be more suitable.

**Library Used**

There is no explicit library mentioned in the benchmark. However, both approaches use built-in JavaScript methods (`...` and `Object.assign()`).

**Special JS Features/Syntax**

The benchmark uses the spread operator (`...`) and `Object.assign()`, which are built-in features of JavaScript. These features are widely supported by modern browsers and are an essential part of the language.

**Alternatives**

Other alternatives for merging objects in JavaScript include:

* Using `lodash` library's `merge()` method
* Using `immer` library's `with` function
* Using `react` library's `useMemo` hook with a merge function
* Writing custom merge functions using loops or recursion

These alternatives might offer different trade-offs between performance, readability, and complexity.

Related benchmarks:

Javascript Spread vs Object.Assign (to {}) (version: 0)

Comparing performance of: Spread vs Object.assign

Created: 3 years ago by: Guest

Jump to the latest result

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):