Benchmark: Fair lodash merge vs object.assign vs spread

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: 'my' }; var b = { c: 'goddess' }; var c = _.merge({}, a, b);
object.assign
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = Object.assign({}, a, b);
spread
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; 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: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36

Browser/OS: Chrome 89 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
lodash merge	1729301.1 Ops/sec
object.assign	4910789.0 Ops/sec
spread	2133052.5 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark compares the performance of three JavaScript methods for merging two objects: `_.merge` from Lodash, `Object.assign`, and the spread operator (`{ ...a, ...b }`). The goal is to determine which method is the fastest in terms of execution time.

**Test Cases**

Each test case consists of a short script that defines two objects, `a` and `b`, and then attempts to merge them using one of the three methods. The resulting merged object is stored in variable `c`.

1. **Lodash Merge**: `_ = require('lodash'); var c = _.merge({}, a, b);`
2. **Object Assign**: `var c = Object.assign({}, a, b);`
3. **Spread Operator**: `var c = { ...a, ...b };`

**Options Compared**

The benchmark compares the performance of three different approaches:

* **Lodash Merge (`_.merge`)**: uses the Lodash library to merge two objects.
* **Object Assign (`Object.assign`)**: a built-in JavaScript method for merging two or more objects into one.
* **Spread Operator (`{ ...a, ...b }`)**: a new syntax introduced in ECMAScript 2018 that allows merging two objects using the spread operator.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Lodash Merge (`_.merge`)**
	* Pros:
		+ Robustness: Lodash provides a well-tested and widely adopted implementation.
		+ Flexibility: can merge objects with nested properties.
	* Cons:
		+ Overhead: requires loading the entire Lodash library, which may add unnecessary overhead.
2. **Object Assign (`Object.assign`)**
	* Pros:
		+ Built-in method: no additional library required.
		+ Simple syntax: easy to read and understand.
	* Cons:
		+ Limited flexibility: only merges two objects; nested properties require additional code.
3. **Spread Operator (`{ ...a, ...b }`)**
	* Pros:
		+ Concise syntax: easy to write and read.
		+ Fast: has a low overhead since it only requires creating a new object.
	* Cons:
		+ Limited support: not supported in older browsers or Node.js versions.

**Library Usage**

The `_.merge` function from Lodash is used for its robustness and flexibility. The `Object.assign` method is built into JavaScript, making it a lightweight option with simple syntax. The spread operator is a new syntax introduced in ECMAScript 2018, providing a concise way to merge objects.

**Special JS Feature/Syntax**

The spread operator (`{ ...a, ...b }`) is a relatively recent feature introduced in ECMAScript 2018. It allows merging two objects using a concise syntax that is easy to read and write.

**Other Alternatives**

If you need more control over the merge process or require support for older browsers, consider alternative methods:

* **Using `Array.prototype.concat()`**: can be used to merge arrays, but may not work as expected with objects.
* **Using a custom merge function**: can provide flexibility and control, but may add unnecessary complexity.

Keep in mind that this benchmark only compares the performance of these three specific methods. Depending on your use case, you may need to consider other factors, such as code readability, maintainability, or additional features required for your application.

Related benchmarks:

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

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

Created: 3 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 2 months ago):