Benchmark: 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', d: 'ss' }; var b = { c: 'goddess', d: 's2s' }; var c = _.merge(a, b);
object.assign
var a = { a: 'oh', b: 'my', d: 'ss' }; var b = { c: 'goddess', d: 's2s' }; var c = Object.assign(a, b);
spread
var a = { a: 'oh', b: 'my', d: 'ss' }; var b = { c: 'goddess', d: 's2s' }; 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

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

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Let's break down the provided benchmark and explain what is being tested, along with the pros and cons of each approach.

**Benchmark Purpose:**
The test measures the performance difference between three methods for merging objects in JavaScript:

1. Using `_.merge` from Lodash
2. Using `Object.assign`
3. Using the spread operator (`...`)

**Library Used:**
Lodash is a popular utility library that provides a wide range of functions for tasks like array manipulation, string manipulation, and object manipulation.

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) as a new way to create objects by merging multiple sources into one. It's a shorthand way of writing `Object.assign()` with an array of properties.

**Options Compared:**
We have three options compared:

1. **_.merge**: This is the Lodash function specifically designed for merging objects.
2. **Object.assign**: This is a built-in JavaScript method that merges all enumerable own properties of source objects into a target object.
3. **Spread operator (`...`)**: This is a shorthand way to create an object by merging multiple sources.

**Pros and Cons:**

1. **_.merge**:
	* Pros: Designed specifically for merging objects, handles nested objects, and can be more efficient in some cases.
	* Cons: Requires Lodash library, which may add unnecessary overhead for small projects.
2. **Object.assign**:
	* Pros: Built-in JavaScript method, widely supported across browsers and Node.js versions.
	* Cons: Can be slower than _.merge or the spread operator due to its more verbose syntax and additional checks for null/undefined values.
3. **Spread operator (`...`)**:
	* Pros: Shorthand way of writing `Object.assign()`, efficient, and widely supported across modern browsers and Node.js versions.
	* Cons: Requires ES6+ support, which may not be available in older browsers or environments.

**Other Considerations:**

* The spread operator is generally considered a good choice for merging objects due to its concise syntax and performance.
* If you're using Lodash, _.merge can provide additional benefits like handling nested objects more efficiently. However, it also requires the library to be loaded, which may add unnecessary overhead.
* Object.assign remains a viable option when working with older browsers or environments that don't support ES6+ features.

**Other Alternatives:**

* If you're looking for alternative libraries for object merging, some popular options include:
	+ **Merges**: A lightweight library designed specifically for merging objects.
	+ **Immutable.js**: A library that provides a functional programming approach to data manipulation, including object merging.
* For custom implementations, you can use the `Object.assign()` method directly or write your own merging function using a loop or recursion.

Related benchmarks:

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>

Fastest: N/A

Slowest: N/A

No previous run results

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