Benchmark: lodash merge vs object.assign vs spread 3984398

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: 1, b: 2, c: 3, d: 4, e: 5, f: 6}; var b = {a: 10, b: 20, c: 30, d: 40, e: 50, f: 60}; var c = _.merge(a, b);
object.assign
var a = {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6}; var b = {a: 10, b: 20, c: 30, d: 40, e: 50, f: 60}; var c = Object.assign(a, b);
spread
var a = {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6}; var b = {a: 10, b: 20, c: 30, d: 40, e: 50, f: 60}; 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: 7 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:143.0) Gecko/20100101 Firefox/143.0

Browser/OS: Firefox 143 on Linux

View result in a separate tab

Test name	Executions per second
lodash merge	5990750.5 Ops/sec
object.assign	20650742.0 Ops/sec
spread	4989786.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The test consists of three individual microbenchmarks that compare the performance of three different methods for merging two objects:

1. Lodash `merge` function
2. `Object.assign()` method
3. Spread operator (`...`)

Each test case provides a script definition, which is used to create and run a benchmark.

**Script Definition**

The script definition is a JavaScript code snippet that creates two objects, `a` and `b`, with similar properties but different values. The script then uses each of the three methods to merge these two objects into a new object, `c`.

Here's an excerpt from one of the test cases:
```javascript
var a = {a: 1, b: 2, c: 3, d: 4, e: 5, f: 6};
var b = {a: 10, b: 20, c: 30, d: 40, e: 50, f: 60};
var c = _.merge(a, b); // Lodash merge
```
**Methods Being Tested**

1. **Lodash `merge` function**: The `_` variable refers to the Lodash library, which provides a set of utility functions for functional programming. The `merge` function takes two objects as input and returns a new object with merged properties.
2. **`Object.assign()` method**: This is a built-in JavaScript method that takes multiple source objects and merges them into a target object.
3. **Spread operator (`...`)**: This is a syntax introduced in ECMAScript 2018, which allows you to merge two objects using the spread operator.

**Options Compared**

The benchmark compares the performance of each method across different devices (Android) with various browsers (Chrome Mobile).

**Pros and Cons of Each Method**

1. **Lodash `merge` function**: Pros:
	* Can handle complex merge scenarios, including arrays and nested objects.
	* Provides a more explicit way of merging objects.
Cons:
	* Requires the Lodash library to be included in the project.
	* May have overhead due to the library's complexity.
2. **`Object.assign()` method**:
	* Pros:
		+ Built-in, so no additional libraries are required.
		+ Simple and lightweight.
	* Cons:
		+ Only supports merging objects with similar keys.
		+ Returns a new object, which can be inefficient for large datasets.
3. **Spread operator (`...`)**:
	* Pros:
		+ Simple and concise syntax.
		+ Supports merging objects with different types of values (e.g., numbers, strings, arrays).
	* Cons:
		+ Only supports merging objects with similar keys.
		+ Limited support for complex merge scenarios.

**Library Used**

Lodash is a popular JavaScript library that provides a set of utility functions for functional programming. It's widely used in web development and can be included via a CDN (Content Delivery Network) or by installing it as a dependency in your project.

**Special JS Feature/Syntax**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018. It allows you to merge two objects using the syntax `object1 {... object2}`.

**Alternatives**

Other alternatives for merging objects include:

* Using a library like jQuery or Underscore.js, which provides similar functionality.
* Implementing a custom merge function using a combination of `Object.keys()` and `reduce()`.
* Using a different data structure, such as an array of key-value pairs, to avoid the need for explicit merging.

I hope this explanation helps you understand what's being tested in the provided benchmark!

Related benchmarks:

lodash merge vs object.assign vs spread 3984398 (version: 0)

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

Created: 4 years ago by: Guest

Jump to the latest result

lodash merge

object.assign

spread

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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