Benchmark: 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

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmarking test cases.

**Benchmark Definition**

The benchmark measures the performance of three approaches to merge two objects in JavaScript: `_.merge` from Lodash, `Object.assign`, and the spread operator (`...`). The purpose of this benchmark is to compare the efficiency of these approaches when merging two objects with different properties.

**Options Compared**

* `_._merge`: This function merges two objects into a new object.
	+ Pros: Easy to use, straightforward syntax.
	+ Cons: May have performance overhead due to its own implementation logic.
* `Object.assign()`: This method copies the values of an object from one or more source objects to a target object.
	+ Pros: Fast and efficient, widely supported.
	+ Cons: Syntax can be verbose for complex merges.
* Spread Operator (`...`): This operator merges two or more objects into a new object.
	+ Pros: Concise syntax, easy to read.
	+ Cons: Not all browsers support the spread operator.

**Library Used**

The `_.merge()` function is part of Lodash, a popular JavaScript utility library that provides various functional programming helpers. The purpose of Lodash is to simplify common tasks and make code more concise.

**Special JS Feature/Syntax**

* None mentioned in this benchmark. However, note that the spread operator (`...`) was introduced in ECMAScript 2018 (ES8) and might not be supported by older browsers.

**Other Considerations**

When choosing between these approaches, consider the following factors:

* Code readability: If code maintainability is important, `_.merge()` or the spread operator might be a better choice due to their concise syntax.
* Performance-critical code: For critical performance paths, `Object.assign()` might be the most efficient option due to its native implementation and fast execution.

**Alternatives**

If you need alternative approaches for merging objects in JavaScript:

* Use the recursive merge function from another library like `jsonmerge`.
* Implement your own merge function using techniques like union or intersection.
* Consider using a JSON serialization/deserialization library that provides merge functionality.

Keep in mind that these alternatives might not be as efficient or widely supported as the options covered in this benchmark.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:74.0) Gecko/20100101 Firefox/74.0

Browser/OS: Firefox 74 on Linux

View result in a separate tab

Test name	Executions per second
lodash merge	1349879.2 Ops/sec
object.assign	1507804.0 Ops/sec
spread	1973304.1 Ops/sec

Related benchmarks:

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

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

Created: 5 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 26 days ago):