Benchmark: lodash merge vs object.assign vs spread with larger data and no mutation

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 = { "_id": "624863161dde7aa8538857e6", "index": 0, "guid": "4be322b0-459c-41aa-bd09-f3227cd353df", "isActive": false, "balance": "$3,816.12", "picture": "http://placehold.it/32x32", "age": 26, "eyeColor": "brown", "name": "Caitlin Beach", "gender": "female", "company": "MICROLUXE", "email": "caitlinbeach@microluxe.com", "phone": "+1 (954) 462-3548", "address": "854 Sapphire Street, Biddle, Colorado, 1002", "about": "Adipisicing proident labore qui est minim tempor. Ipsum est cillum nisi exercitation laboris irure. Enim tempor elit quis est deserunt cupidatat dolore. Mollit aliquip enim proident non commodo non sunt tempor nisi elit. Deserunt ex proident mollit esse. Ea Lorem sit ipsum occaecat ad ullamco.\r\n", "registered": "2018-03-22T05:20:17 +07:00", "latitude": 69.438455, "longitude": 113.552142 }; var b = { "eyeColor": "bdrown", "name": "Caitlind Beach", "gender": "femalde", "company": "MICRdOLUXE", "email": "caitlindbeach@microluxe.com", "phone": "+1 (954)d 462-3548", }; var c = _.merge(a, b);
object.assign
var a = { "_id": "624863161dde7aa8538857e6", "index": 0, "guid": "4be322b0-459c-41aa-bd09-f3227cd353df", "isActive": false, "balance": "$3,816.12", "picture": "http://placehold.it/32x32", "age": 26, "eyeColor": "brown", "name": "Caitlin Beach", "gender": "female", "company": "MICROLUXE", "email": "caitlinbeach@microluxe.com", "phone": "+1 (954) 462-3548", "address": "854 Sapphire Street, Biddle, Colorado, 1002", "about": "Adipisicing proident labore qui est minim tempor. Ipsum est cillum nisi exercitation laboris irure. Enim tempor elit quis est deserunt cupidatat dolore. Mollit aliquip enim proident non commodo non sunt tempor nisi elit. Deserunt ex proident mollit esse. Ea Lorem sit ipsum occaecat ad ullamco.\r\n", "registered": "2018-03-22T05:20:17 +07:00", "latitude": 69.438455, "longitude": 113.552142 }; var b = { "eyeColor": "bdrown", "name": "Caitlind Beach", "gender": "femalde", "company": "MICRdOLUXE", "email": "caitlindbeach@microluxe.com", "phone": "+1 (954)d 462-3548", }; var c = Object.assign({}, a, b);
spread
var a = { "_id": "624863161dde7aa8538857e6", "index": 0, "guid": "4be322b0-459c-41aa-bd09-f3227cd353df", "isActive": false, "balance": "$3,816.12", "picture": "http://placehold.it/32x32", "age": 26, "eyeColor": "brown", "name": "Caitlin Beach", "gender": "female", "company": "MICROLUXE", "email": "caitlinbeach@microluxe.com", "phone": "+1 (954) 462-3548", "address": "854 Sapphire Street, Biddle, Colorado, 1002", "about": "Adipisicing proident labore qui est minim tempor. Ipsum est cillum nisi exercitation laboris irure. Enim tempor elit quis est deserunt cupidatat dolore. Mollit aliquip enim proident non commodo non sunt tempor nisi elit. Deserunt ex proident mollit esse. Ea Lorem sit ipsum occaecat ad ullamco.\r\n", "registered": "2018-03-22T05:20:17 +07:00", "latitude": 69.438455, "longitude": 113.552142 }; var b = { "eyeColor": "bdrown", "name": "Caitlind Beach", "gender": "femalde", "company": "MICRdOLUXE", "email": "caitlindbeach@microluxe.com", "phone": "+1 (954)d 462-3548", }; 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 28 days ago):

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance of three different methods to merge two objects in JavaScript:

1. `_.merge` (Lodash library)
2. `Object.assign`
3. `Spread Operator` (`{...a, ...b}`)

**Options Compared**

Each test case compares the execution time of a single run of each method.

**Methods Breakdown**

1. **`.merge` (Lodash)**: Uses the `lodash.merge` function to merge two objects.
2. **`Object.assign`**: Uses the `Object.assign()` method to create a new object and copy properties from the first object into it, then copies properties from the second object into the resulting object.
3. **`Spread Operator`**: Uses the spread operator (`{...a, ...b}`) to merge two objects.

**Performance Results**

The latest benchmark results show that:

* `spread` is the fastest method with an average execution time of 818,108,830 executions per second (Chrome 100).
* `_.merge` is slower than `spread`, but faster than `Object.assign`. Its average execution time is 170,918,330 executions per second.
* `Object.assign` is the slowest method, with an average execution time of 160,176,070 executions per second.

**Conclusion**

The spread operator appears to be the most efficient way to merge two objects in JavaScript, followed closely by Lodash's `.merge` function. The `Object.assign` method is slower due to its overhead and the need to create a new object for each copy operation.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.60 Safari/537.36 Edg/100.0.1185.29

Browser/OS: Chrome 100 on Windows

View result in a separate tab

Test name	Executions per second
lodash merge	1709183.1 Ops/sec
object.assign	1601761.8 Ops/sec
spread	8181083.0 Ops/sec

Related benchmarks:

lodash merge vs object.assign vs spread with larger data and no mutation (version: 0)

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

Created: 2 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 28 days ago):