Benchmark: Object.assign vs _.defaultsDeep

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var schema = {
  name: undefined,
  password: undefined,
  photo: undefined,
  role: 1,
  level: 1,
  resPass: false,
  stories: {
  	one: 'Hola mundo',
    two: false,
    three: false
  }
}

var user = {
  name: "Jacob",
  password: 123,
  photo: "img.jpg",
  stories: {
    two: "Adios mundo"
  }
}

Tests:

Object.assign
let objectAssign = Object.assign({}, schema, user); objectAssign.stories = Object.assign(schema.stories, user.stories); console.log(objectAssign);
_.defaults
const defaultsDeep = _.defaultsDeep(schema, user); console.log(defaultsDeep);

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Object.assign

414K/s

_.defaults

377K/s

View exact numbers

✓ Object.assign: 413,513 ops/sec
• _.defaults: 376,722 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
_.defaults

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Object.assign

410K/s

_.defaults

370K/s

View exact numbers

Test name	Executions per second
✓ Object.assign	409,639 Ops/sec
_.defaults	370,385 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 provided benchmark.

**Overview**

The benchmark compares two JavaScript functions: `Object.assign` and `_defaultDeep` (a function from the Lodash library). The goal is to measure which function is faster when used to merge objects.

**Options Compared**

There are two options being compared:

1. **Object.assign**: A built-in JavaScript method that merges all own enumerable properties of source objects into a target object.
2. **_.defaultsDeep` (from Lodash): A function that returns a new object with the default values for each key in the schema, merged with the provided user object.

**Pros and Cons**

* **Object.assign**:
	+ Pros: Built-in JavaScript method, easy to use, and fast.
	+ Cons: Can be slow if the number of properties is large, as it iterates over all properties.
* **_.defaultsDeep` (Lodash):
	+ Pros: Optimized for performance, handles nested objects, and can be faster than `Object.assign` for large datasets.
	+ Cons: Requires an external library (Lodash), which may add overhead.

**Library Description**

The benchmark uses Lodash, a popular JavaScript utility library. `_defaultDeep` is a function that recursively merges two objects by setting default values for missing keys. In this case, it's used to merge the `schema` object with the `user` object.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax being tested in this benchmark.

**Other Alternatives**

If you don't want to use Lodash, you can implement a similar function using JavaScript:

```javascript
function defaultDeep(schema, user) {
  const result = {};
  for (const key in schema) {
    if (!user[key]) {
      result[key] = schema[key];
    } else if (typeof schema[key] === 'object' && typeof user[key] === 'object') {
      result[key] = defaultDeep(schema[key], user[key]);
    }
  }
  return result;
}
```

However, this implementation might not be as optimized or efficient as the Lodash version.

**Benchmark Preparation**

The benchmark prepares two objects: `schema` and `user`. The `schema` object has some properties with default values (e.g., `role`, `level`) and some properties that are undefined (e.g., `name`, `password`). The `user` object has some properties that are defined (e.g., `photo`) and some properties that are nested objects.

The benchmark then defines two test cases:

1. Using `Object.assign` to merge the `schema` object with the `user` object, setting `stories` recursively.
2. Using `_defaultsDeep` from Lodash to merge the `schema` object with the `user` object.

Finally, the benchmark runs both tests and measures their execution times using the Chrome browser on a Mac OS X system.

Object.assign vs _.defaultsDeep (version: 0) Benchmark.js

Comparing performance of: `Object.assign vs _.defaults`

Created: 5 years ago by: Guest

Go to the latest result

Object.assign

_.defaults

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Object.assign vs _.defaultsDeep (version: 0) Benchmark.js

Comparing performance of: Object.assign vs _.defaults

Created: 5 years ago by: Guest

Go to the latest result

Object.assign

_.defaults

Historical Performance Data aggregated from 6 community runs

Desktop Results:

Chrome 6 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Object.assign vs _.defaults`