Benchmark: lodash merge vs object.assign vs spread with arrays

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Tests:

lodash merge
var a = { a: 'oh', b: [1, 2, 3] }; var b = { b: [2, 3, 4] }; var c = _.merge(a, b);
object.assign
var a = { a: 'oh', b: [1, 2, 3] }; var b = { b: [2, 3, 4] }; var c = Object.assign(a, b);
spread
var a = { a: 'oh', b: [1, 2, 3] }; var b = { b: [2, 3, 4] }; var c = { ...a, ...b };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
object.assign
spread

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
lodash merge	1223748.2 Ops/sec
object.assign	23179496.0 Ops/sec
spread	18784240.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript libraries and functions is crucial in understanding their efficiency, especially when dealing with complex data structures like objects and arrays.

**Benchmark Definition:**
The benchmark tests the performance of three approaches to merge two objects or arrays:

1.  **Lodash Merge (`_merge` method):** Lodash is a popular JavaScript utility library that provides various helper functions for tasks such as array manipulation, string manipulation, and more.
2.  **Object Assign (`Object.assign()` method):** This is a built-in JavaScript method used to copy the values of all or part of one or more source objects to a target object.
3.  **Spread Operator (with arrays):** The spread operator (`...`) allows you to expand an iterable and use its elements as individual arguments.

**Options Compared:**

*   Lodash Merge
*   Object Assign
*   Spread Operator with Arrays

**Pros and Cons of Each Approach:**

### Lodash Merge:

Pros:

*   Efficient for merging objects with a large number of properties.
*   Provides more control over the merge process, such as specifying which properties to keep or overwrite.

Cons:

*   Adds extra overhead due to the library itself.
*   May not be optimized for performance in all cases.

### Object Assign:

Pros:

*   Built-in method, so no additional library is required.
*   Fast and lightweight execution.

Cons:

*   Can be slower than Lodash Merge for large objects or arrays.
*   Limited control over the merge process.

### Spread Operator (with Arrays):

Pros:

*   Easy to use and understand.
*   No additional libraries are required.

Cons:

*   May be slower than Lodash Merge or Object Assign for very large data structures.
*   Limited control over the merge process.

**Library and Purpose:**

The `lodash` library is a popular JavaScript utility library that provides various helper functions for tasks such as array manipulation, string manipulation, and more. In this benchmark, `lodash.merge` is used to compare its performance with the built-in `Object.assign()` method and the spread operator with arrays.

**Special JS Feature or Syntax:**

The benchmark uses the spread operator (`...`) which is a relatively new feature in JavaScript, introduced in ECMAScript 2018. The syntax allows you to expand an iterable (such as an array) and use its elements as individual arguments.

**Other Alternatives:**

1.  **Immutable.js:** A library that provides immutable data structures and functions for working with them.
2.  **JSON Merge Patch:** A lightweight JSON patching library that can be used for merging objects or arrays.
3.  **Merging libraries like `jsonmerge`**: These are specialized libraries designed specifically for merging JSON data.

In summary, the benchmark tests the performance of three approaches to merge objects or arrays: Lodash Merge (`_merge` method), Object Assign (`Object.assign()` method), and Spread Operator with Arrays. Each approach has its pros and cons, and understanding these can help in choosing the most efficient solution for a specific use case.

Related benchmarks:

lodash merge vs object.assign vs spread with arrays (version: 0)

Comparing performance of: lodash merge vs object.assign vs spread

Created: 6 years ago by: Guest

Jump to the latest result

lodash merge

object.assign

spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):