Benchmark: lodash assign 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 };
lodash assign
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = _.assign(a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
object.assign
spread
lodash assign

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser/OS: Chrome 123 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
lodash merge	3253564.8 Ops/sec
object.assign	5545124.0 Ops/sec
spread	18868264.0 Ops/sec
lodash assign	3911040.8 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 benchmark and its test cases.

**What is being tested?**

The benchmark tests four different ways to merge or assign properties from two objects: Lodash's `merge` function, `assign` function, `object.assign`, and the spread operator (`...`). The objective is to compare their performance in terms of execution speed.

**Options compared:**

1. **Lodash `merge`**: A utility function that merges two objects into a new object.
2. **Lodash `assign`**: A utility function that assigns properties from one object to another.
3. **`object.assign`**: A built-in JavaScript method that assigns properties from one object to another.
4. **Spread operator (`...`)**: A feature introduced in ECMAScript 2015, which allows creating a new object by spreading the properties of an existing object.

**Pros and Cons:**

1. **Lodash `merge`**:
	* Pros: Convenient utility function with optional options for merging, less boilerplate code.
	* Cons: External dependency on Lodash, may introduce overhead due to library loading.
2. **Lodash `assign`**:
	* Pros: Similar to `merge`, but with a single method that can be used for assignment.
	* Cons: Also introduces an external dependency on Lodash.
3. **`object.assign`**:
	* Pros: Built-in JavaScript method, no dependencies or overhead.
	* Cons: May require creating an empty object as the target, and its behavior is not explicitly stated in older browsers.
4. **Spread operator (`...`)**:
	* Pros: Concise syntax, well-supported across modern browsers and environments.
	* Cons: May not work with older browsers that don't support it.

**Library used:**

Lodash (version 4.17.5) is used as the utility library for `merge` and `assign` functions. Lodash provides a set of higher-order functions, including `merge` and `assign`, which can be useful in many situations.

**Special JS feature or syntax:**

The spread operator (`...`) is a relatively new JavaScript feature introduced in ECMAScript 2015. It allows creating a new object by spreading the properties of an existing object, making it concise and expressive.

**Other alternatives:**

In addition to the options mentioned above, there are other ways to merge or assign properties from two objects:

* `Object.assign()` with an empty object as the target
* Using the `for...in` loop and assigning each property individually
* Implementing a custom merge function using recursion

However, these alternatives may be less efficient, more verbose, or not supported in older browsers.

Related benchmarks:

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

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

Created: 7 years ago by: Registered User

Jump to the latest result

lodash merge

object.assign

spread

lodash assign

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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