Benchmark: Lodash vs Object.assign

HTML Preparation code:

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

Script Preparation code:

function isObject(item) {
  return (item && typeof item === 'object' && !Array.isArray(item));
}

function mergeDeep(target, ...sources) {
  if (!sources.length) return target;
  const source = sources.shift();

  if (isObject(target) && isObject(source)) {
    for (const key in source) {
      if (isObject(source[key])) {
        if (!target[key]) Object.assign(target, { [key]: {} });
        mergeDeep(target[key], source[key]);
      } else {
        Object.assign(target, { [key]: source[key] });
      }
    }
  }
  return mergeDeep(target, ...sources);
}

Tests:

Lodash
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = _.merge(a, b);
mergeDeep using object.assign
var a = { a: 'oh', b: 'my' }; var b = { c: 'goddess' }; var c = mergeDeep(a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Lodash
mergeDeep using object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

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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's being tested, compared, and its pros and cons.

**Benchmark Definition**

The benchmark compares two approaches for merging objects in JavaScript:

1. **Lodash**: The `mergeDeep` function from Lodash is used to merge two objects recursively.
2. **Object.assign**: A custom implementation using the `Object.assign` method to merge two objects.

**What's being tested?**

The benchmark tests the performance of these two approaches, comparing their execution times for merging two objects with a nested structure. The test case consists of an object `a` and another object `b`, which are merged into a new object `c`.

**Options compared**

* **Lodash**: Uses the `mergeDeep` function from Lodash, which recursively merges objects by iterating over the properties of both objects.
* **Object.assign**: Uses the `Object.assign` method to merge two objects. This approach only works for shallow merges and will overwrite existing properties.

**Pros and Cons**

* **Lodash (mergeDeep)**:
	+ Pros:
		- Recursively merges objects, handling nested structures.
		- Handles array-like values and null/undefined cases.
	+ Cons:
		- Requires the Lodash library, which may add overhead.
		- May be slower due to the recursive function calls.
* **Object.assign**:
	+ Pros:
		- Simple and lightweight implementation.
		- Only requires the built-in `Object.assign` method.
	+ Cons:
		- Only works for shallow merges (i.e., not handling nested structures).
		- Will overwrite existing properties, potentially causing unexpected behavior.

**Library usage**

The benchmark uses Lodash's `mergeDeep` function, which is a utility function designed to recursively merge objects. The purpose of this library is to provide a convenient and efficient way to handle object merges in JavaScript.

**Special JS feature or syntax**

There are no special features or syntax used in this benchmark. It only relies on standard JavaScript language constructs.

**Benchmark preparation code**

The provided `Script Preparation Code` sets up the necessary variables and functions for the test cases, including the `isObject` function and the `mergeDeep` implementation using Lodash.

**Other alternatives**

If you wanted to implement object merging without relying on Lodash or `Object.assign`, you could use alternative approaches such as:

* Recursively iterating over object properties using `for...in` loops.
* Using a recursive function with base cases for shallow and deep merges.
* Leveraging existing library functions, like Immutable.js's `merge` method.

Keep in mind that these alternatives may not be as concise or efficient as the provided implementations.

Related benchmarks:

Lodash vs Object.assign (version: 0)

Testing the performance of different approach

Comparing performance of: Lodash vs mergeDeep using object.assign

Created: 4 years ago by: Guest

Jump to the latest result

Lodash

mergeDeep using object.assign

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):