Benchmark: spread vs object assign new object

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, firstObject, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested, compared, and discussed.

**Benchmark Overview**

The benchmark is comparing two ways to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`.

**Options Compared**

Two options are being compared:

1. **Using the spread operator (`...`)**: This method uses the rest syntax to create a new object with merged properties from two source objects.
2. **Using `Object.assign()`**: This method creates a new object by copying all enumerable own properties from one or more source objects.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

* **Using the spread operator (`...`)**:
	+ Pros:
		- More concise and readable code
		- Can handle nested objects and arrays
		- Less overhead compared to `Object.assign()`
	+ Cons:
		- May not be supported in older browsers (prior to Chrome 57)
		- Can lead to unexpected behavior if not used carefully (e.g., when merging objects with different property names)
* **Using `Object.assign()`**:
	+ Pros:
		- More widely supported across browsers
		- Easy to use and understand, especially for those familiar with the method
	+ Cons:
		- Less concise than using the spread operator
		- Can lead to more overhead compared to the spread operator

**Library/Function Used**

In both test cases, no libraries or functions are used beyond built-in JavaScript features.

**Special JS Feature/Syntax**

The benchmark uses a feature introduced in ECMAScript 2018: the rest syntax (`...`), which allows for spreading array-like objects into new objects. This syntax is also supported by other modern browsers and can be used as an alternative to `Object.assign()` for merging objects.

**Other Alternatives**

If you need more control over object merging or want to support older browsers, you might consider using:

* **Lodash's `merge()` function**: A popular utility library that provides a robust way to merge objects, handling various edge cases and edge use cases.
* **Merge functions from other libraries**: Other libraries like Moment.js (for date merging) or deepmerge (for more complex object merges) offer alternative solutions.

Keep in mind that these alternatives might introduce additional dependencies or complexity compared to the built-in JavaScript methods.

Related benchmarks:

spread vs object assign new object (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 3 years ago by: Registered User

Jump to the latest result

Using the spread operator

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):