Benchmark: merge vs object.assign vs spread12

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

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

Latest run results:

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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 and explain what's being tested.

**What is being tested?**

The test cases compare three different approaches to merge two objects:

1. **Lodash `merge`**: The Lodash library provides a utility function called `_.merge()` that merges two objects recursively.
2. **ES6 `Object.assign`**: This method creates a new object with the properties of two or more source objects passed as an argument.
3. **Spread syntax (`...`)**: This is a shorthand way to create a new object with the properties of one or more source objects.

**Options compared**

The three options are being compared in terms of their performance, which is measured by the number of executions per second on a specific test case.

**Pros and cons of each approach**

* **Lodash `merge`**: Pros:
	+ Recursive merging, which means it can handle nested objects.
	+ Can be more readable for complex merge scenarios.
* Cons:
	+ Requires an external library (Lodash), which may add overhead.
* **ES6 `Object.assign`**: Pros:
	+ Native to JavaScript, so no additional libraries are required.
	+ Fast and efficient.
* Cons:
	+ Only merges surface-level properties; nested objects must be handled separately.
* **Spread syntax (`...`)**: Pros:
	+ Concise and expressive way to create a new object with merged properties.
	+ Works well for simple merge scenarios.
* Cons:
	+ Can lead to unexpected behavior if not used carefully (e.g., when merging objects with conflicting property names).

**Library usage**

In this benchmark, the Lodash library is used in one of the test cases (`lodash.merge`), but it's not explicitly mentioned in any other test case. This suggests that performance differences between these approaches might be significant.

**Special JS feature or syntax**

There doesn't seem to be any special JavaScript features or syntax being tested here; the benchmark focuses on comparing three established methods for merging objects.

**Other alternatives**

If `Object.assign` and spread syntax are not sufficient, other options could include:

* Using a custom function to merge objects (e.g., a recursive function that checks for existing properties).
* Using a third-party library like jQuery's `$.extend()` method.
* Implementing a more complex merging strategy using JavaScript's built-in `Object` methods.

Keep in mind that these alternatives may add complexity and overhead compared to the simple approaches used in this benchmark.

Related benchmarks:

merge vs object.assign vs spread12 (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):