Benchmark: JavaScript spread operator vs Object.assign performance (empty object, actually equivalents)

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

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

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**Benchmark Overview**

The provided benchmark measures the performance of two approaches for merging objects in JavaScript: the spread operator (`...`) and `Object.assign()`. The test cases use identical input data, with one object containing a single property (`firstObject`) and another object containing multiple properties (`secondObject`). The final object is created by merging these two objects using either method.

**Options Compared**

The benchmark compares two options:

1. **Spread Operator ( ... )**: This approach uses the spread operator to merge the two objects, which creates a new object with all the key-value pairs from both objects.
2. **Object.assign()**: This approach uses the `Object.assign()` method to merge the two objects, which also creates a new object with all the key-value pairs from both objects.

**Pros and Cons**

* **Spread Operator ( ... )**:
	+ Pros: concise, readable, and efficient for merging simple objects.
	+ Cons: can be less efficient than `Object.assign()` for large or complex objects, as it involves creating a new object with all the key-value pairs.
* **Object.assign()**:
	+ Pros: efficient for large or complex objects, as it only copies the specified properties from one object to another.
	+ Cons: less readable and concise than the spread operator.

**Library/Functionality**

In this benchmark, the `Object.assign()` method is used as a library function to merge the two objects. This approach relies on the implementation details of `Object.assign()`, which may vary across different browsers or JavaScript engines.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntaxes being tested in this benchmark. The focus is solely on comparing two approaches for merging objects.

**Other Alternatives**

For merging objects, other alternatives include:

1. **Destructuring assignment**: This approach uses destructuring assignment to merge the two objects, which can be more concise and expressive than `Object.assign()`. However, it may not be as efficient as the spread operator or `Object.assign()` for large or complex objects.
2. **Array methods**: In some cases, you can use array methods like `concat()` or `spread` to merge arrays or objects. While this approach works for merging arrays, it's less suitable for merging objects.

In summary, this benchmark provides a simple and concise way to compare the performance of two approaches for merging objects in JavaScript: the spread operator and `Object.assign()`.

Related benchmarks:

JavaScript spread operator vs Object.assign performance (empty object, actually equivalents) (version: 0)

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

Created: 3 years ago by: Guest

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):