Benchmark: _.merge vs assign vs spread

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js'></script>

Tests:

_.merge
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = _.merge(a, b);
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
_.merge
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/605.1.15 (KHTML, like Gecko) Version/14.1 Safari/605.1.15

Browser/OS: Safari 14 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
_.merge	2445658.8 Ops/sec
assign	2744750.2 Ops/sec
spread	5029225.5 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case on the MeasureThat.net website. The benchmark compares the performance of three different approaches to merge two objects: _.merge, Object.assign, and spread syntax.

**Approaches Compared**

1. **_.merge**: This approach uses the Lodash library's merge function to combine two objects.
2. **Object.assign**: This is a built-in JavaScript method that assigns the properties of one or more source objects to a target object.
3. **Spread syntax**: This approach uses the spread operator (e.g., `{ ...a, ...b }`) to create a new object by merging the properties of two existing objects.

**Pros and Cons**

* _.merge:
	+ Pros: Easy to use, efficient, and well-documented in Lodash library.
	+ Cons: Requires an additional library import, which may add overhead.
* Object.assign:
	+ Pros: Built-in method, easy to use, and optimized for performance.
	+ Cons: Only works with objects as source and target, and can lead to unexpected behavior if not used carefully.
* Spread syntax:
	+ Pros: Easy to read and write, efficient, and widely supported in modern JavaScript engines.
	+ Cons: Introduced in ECMAScript 2018 (ES2018), which may not be compatible with older browsers or environments.

**Library and Purpose**

The Lodash library is a popular utility library for JavaScript that provides various functions for tasks like array manipulation, object transformation, and more. In this benchmark, _.merge is used to combine two objects.

**JavaScript Features and Syntax**

The spread syntax (`{ ...a, ...b }`) was introduced in ECMAScript 2018 (ES2018) as a new way to create new objects by merging properties from existing objects. This syntax is widely supported in modern JavaScript engines, but may not be compatible with older browsers or environments.

**Alternative Approaches**

Other approaches to merge two objects include:

* Using the `Object.keys()` method and iterating over its results to combine object properties.
* Using a library like underscore.js (similar to Lodash) that provides a `_.merge` function.
* Implementing a custom merge function using recursion or iteration.

Each approach has its pros and cons, and the choice of which one to use depends on the specific requirements of the project.

Related benchmarks:

_.merge vs assign vs spread (version: 0)

Comparing performance of: _.merge vs assign vs spread

Created: 3 years ago by: Guest

Jump to the latest result

_.merge

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):