Benchmark: lodash merge vs lodash assign vs object.assign vs spread - 3 Levels

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js'></script>

Tests:

lodash merge
var a = { a: 'oh', b: 'my', d: { x: 1, z: { a: 'a' } } }; var b = { c: 'goddess', d: { x: 2, y: 99, z: { a: 'b' } } }; var c = _.merge(a, b);
lodash assign
var a = { a: 'oh', b: 'my', d: { x: 1, z: { a: 'a' } } }; var b = { c: 'goddess', d: { x: 2, y: 99, z: { a: 'b' } } }; var c = _.assign(a, b);
spread
var a = { a: 'oh', b: 'my', d: { x: 1, z: { a: 'a' } } }; var b = { c: 'goddess', d: { x: 2, y: 99, z: { a: 'b' } } }; var c = { ...a, ...b };
assign
var a = { a: 'oh', b: 'my', d: { x: 1, z: { a: 'a' } } }; var b = { c: 'goddess', d: { x: 2, y: 99, z: { a: 'b' } } }; var c = Object.assign({}, a, b);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash merge
lodash assign
spread
assign

Fastest: N/A

Slowest: N/A

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

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Let's break down the benchmark and its various components.

**Benchmark Definition:**

The benchmark is designed to compare four different methods for merging or combining two objects in JavaScript:

1. `_.merge` (Lodash): A function that merges two objects into one, recursively iterating through the keys of both objects.
2. `_.assign` (Lodash): A function that copies all own enumerable properties from one object to another.
3. `{ ...a, ...b }`: The spread operator, which creates a new object with the same keys as both `a` and `b`, and values from both objects.
4. `Object.assign({}, a, b)`: A method that merges two objects into one, similar to `_.merge`.

**Options Compared:**

* **Lodash merge (`_.merge`) vs Lodash assign (`_.assign`)**: Both functions are designed for merging objects, but they have different behavior:
	+ `_.merge` recursively iterates through the keys of both objects, while `_.assign` only copies own enumerable properties.
	+ In general, if you need to merge complex objects with nested properties, `_.merge` is a better choice. If you're working with simple objects and don't want to merge any unnecessary properties, `_.assign` might be sufficient.
* **Spread operator (`{ ...a, ...b }`) vs Object.assign():** Both methods create a new object by combining the values of two other objects. However:
	+ The spread operator is more concise and readable, especially for simple objects.
	+ `Object.assign()` can be slower because it checks if the objects are arrays before merging them.

**Pros and Cons:**

* **Lodash merge (`_.merge`)**:
	+ Pros: Recursively merges complex objects with nested properties; robust error handling.
	+ Cons: Can be slower due to recursion; may have higher memory overhead.
* **Lodash assign (`_.assign`)**:
	+ Pros: Faster and more lightweight than `_.merge`.
	+ Cons: Does not recursively merge objects, which can lead to unexpected behavior if the objects are deeply nested.
* **Spread operator (`{ ...a, ...b }`)**:
	+ Pros: Concise, readable, and fast; creates a new object without modifying the original.
	+ Cons: Limited to merging two simple objects; does not work with arrays or complex objects.
* **Object.assign():**
	+ Pros: Works with all types of objects (arrays, objects, etc.); can be faster than the spread operator for large objects.
	+ Cons: Can be slower and more memory-intensive than the spread operator; has a higher risk of unexpected behavior if not used carefully.

**Libraries Used:**

* Lodash (version 4.17.11): A popular utility library that provides various functions, including `_.merge` and `_.assign`.

**Special JS Features/Syntax:**

The benchmark uses the spread operator (`{ ...a, ...b }`) and `Object.assign()`, both of which are standard JavaScript features. No special syntax or features are used in this benchmark.

**Other Alternatives:**

* **JSON merge:** For simple object merges with minimal customization, you can use JSON merge libraries like jsonmerge.js.
* **Immer:** A library for functional updates to objects, which can be useful for merging complex objects.
* **Immutable.js:** A library that provides immutable data structures and functions for working with them.

Overall, the benchmark is designed to provide a simple and concise comparison of different methods for merging or combining two objects in JavaScript.

Related benchmarks:

lodash merge vs lodash assign vs object.assign vs spread - 3 Levels (version: 0)

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

Created: 6 years ago by: Guest

Jump to the latest result

lodash merge

lodash assign

spread

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):