Benchmark: JavaScript optimized spread operator vs Object.assign performance

Tests:

Using the spread operator
const secondObject = { moreData: 'foo bar' } const firstObject = { sampleData: 'Hello world', ...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

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 benchmark and explain what's being tested, along with their pros and cons.

**Benchmark Overview**

The test compares the performance of two approaches to merge objects: using the spread operator (`...`) and `Object.assign()`. The benchmark is designed to measure which approach is faster on a desktop machine running Chrome 118.

**Options Compared**

1. **Using the spread operator (`...`)**:
	* Pros:
		+ Concise and readable syntax
		+ Easy to understand and use, even for developers without prior experience with object merging
	* Cons:
		+ May not be as efficient as `Object.assign()` due to the creation of a new array literal
2. **Using `Object.assign()`**:
	* Pros:
		+ Can be more efficient than using the spread operator, especially when dealing with large objects or arrays
		+ Widely supported and recognized syntax
	* Cons:
		+ May have a steeper learning curve for developers unfamiliar with this method

**Library Used**

In both test cases, the `Object.assign()` method is used as-is. The `Object.assign()` function is part of the ECMAScript standard and is implemented in most JavaScript engines.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes mentioned in these test cases.

**Benchmark Preparation Code**

The benchmark preparation code consists of two scripts:

1. `const secondObject = { moreData: 'foo bar' }\r\nconst firstObject = {\r\n\tsampleData: 'Hello world',\r\n  \t...secondObject\r\n};`: This script creates an object `firstObject` with a single property `sampleData`, and then uses the spread operator (`...`) to merge another object `secondObject` into it.
2. `const firstObject = { sampleData: 'Hello world' }\r\nconst secondObject = { moreData: 'foo bar' }\r\nconst finalObject = Object.assign(firstObject, secondObject);`: This script creates two objects, `firstObject` and `secondObject`, and then uses the `Object.assign()` method to merge them into a new object `finalObject`.

**Alternatives**

Other approaches to merging objects in JavaScript include:

1. **Using the `merge()` function from a library like Lodash**: This approach provides more flexibility and customization options, but may introduce additional overhead.
2. **Using the `deepCopy()` function from a library like Immutable.js**: This approach creates an entirely new object, which can be beneficial when dealing with complex data structures.
3. **Implementing a custom merging algorithm**: This approach allows for fine-grained control over the merging process, but may require more effort to implement and maintain.

Overall, the benchmark provides a simple and readable way to compare the performance of two common approaches to object merging in JavaScript.

Related benchmarks:

JavaScript optimized spread operator vs Object.assign performance (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):