Benchmark: Spread vs object assign (when you need new object as output)

Tests:

spread
const obj = { foo: 1, bar: 2 }; const obj2 = {test:3} const res = { ...obj, ...obj2,}
Object.assign
const obj = { foo: 1, bar: 2 }; const obj2 = {test:3} const res = Object.assign({}, obj ,obj2,)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread
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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**Benchmark Definition**

The provided JSON represents a benchmark definition, which outlines two test cases: `Spread` and `Object.assign`. The goal is to compare the performance of creating a new object by spreading an existing object (`{ ...obj, ...obj2 }`) versus using the `Object.assign()` method with multiple arguments (`Object.assign({}, obj , obj2)`).

**Benchmark Options**

There are two primary approaches compared in this benchmark:

1. **Spread Syntax**: This approach uses the spread operator (`...`) to create a new object by copying properties from one or more source objects. The syntax is: `{ ...obj, ...obj2 }`
	* Pros:
		+ Concise and readable
		+ Can be used to merge objects in a more elegant way
	* Cons:
		+ May incur additional overhead due to the creation of a new object
		+ Not all browsers support the spread operator (e.g., older versions of Internet Explorer)
2. **Object.assign()**: This approach uses the `Object.assign()` method with multiple arguments to create a new object by copying properties from one or more source objects. The syntax is: `Object.assign({}, obj, obj2)`
	* Pros:
		+ Well-supported by most browsers
		+ Allows for more control over the merging process (e.g., specifying the order of operations)
	* Cons:
		+ Can be verbose and less readable than the spread syntax
		+ May incur additional overhead due to the creation of a new object

**Library**

There is no specific library used in this benchmark. However, if we were to include a library for error handling or logging, it might be something like `console.error()` or `console.log()`.

**Special JS Feature/Syntax**

The spread operator (`...`) is a relatively recent feature introduced in ECMAScript 2018 (ES10). It allows you to create new objects by copying properties from one or more source objects. Not all browsers support this syntax, but most modern browsers do.

**Other Considerations**

When comparing the performance of these two approaches, it's essential to consider the following factors:

* **Object size**: The larger the object being copied, the more resources are required for creation and iteration.
* **Property count**: The number of properties being copied can also impact performance. More properties mean more iterations and potentially slower execution times.
* **Browser support**: As mentioned earlier, not all browsers support the spread operator. This could introduce inconsistencies in benchmark results.

**Alternatives**

If you're interested in exploring alternative approaches to creating new objects, some options include:

* Using a library like Lodash's `cloneDeep()` or `merge()` functions
* Implementing your own custom copy function using recursion or iteration
* Utilizing a different data structure, such as an array or a Map, for object-like behavior

Keep in mind that the performance differences between these approaches might not be significant in all scenarios. The best approach often depends on the specific requirements and constraints of your project.

Related benchmarks:

Spread vs object assign (when you need new object as output) (version: 11)

Comparing performance of: spread vs Object.assign

Created: 6 years ago by: Registered User

Jump to the latest result

spread

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):