Benchmark: JavaScript spread operator vs Object.assign performance (same specs)

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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**Overview of the Benchmark**

The provided benchmark, "JavaScript spread operator vs Object.assign performance (same specs)", measures the performance difference between two approaches to merge objects in JavaScript: the spread operator (`...`) and `Object.assign()`. The benchmark is designed to test the performance of these two methods under the same conditions.

**Options Compared**

There are only two options compared in this benchmark:

1. **Using the spread operator**: This method uses the spread operator (`...`) to merge the `firstObject` and `secondObject` into a new object, `finalObject`.
2. **Using Object.assign()**: This method uses the `Object.assign()` function to merge the `firstObject` and `secondObject` into a new object, `finalObject`.

**Pros and Cons of Each Approach**

1. **Using the spread operator**:
	* Pros:
		+ More readable and concise code
		+ Less verbose than using `Object.assign()`
	* Cons:
		+ May not be supported in older browsers (although most modern browsers support it)
		+ Can lead to performance issues if not used correctly (e.g., when dealing with large objects or nested objects)
2. **Using Object.assign()**:
	* Pros:
		+ More widely supported across browsers
		+ May perform better than the spread operator in certain scenarios
	* Cons:
		+ Less readable and more verbose code compared to the spread operator
		+ Can be slower due to the function call overhead

**Library Used**

In this benchmark, the `Object.assign()` method is a built-in JavaScript function. No external libraries are required.

**Special JS Feature/Syntax**

The spread operator (`...`) was introduced in ECMAScript 2018 (ES2018) and is supported by most modern browsers. It allows for more concise object merging and destructuring.

**Other Considerations**

When choosing between the spread operator and `Object.assign()`, consider the following:

* Code readability: If code readability is a priority, using the spread operator may be a better choice.
* Browser support: If you need to support older browsers, using `Object.assign()` might be a safer option.
* Performance: In most cases, both methods have similar performance characteristics. However, if you're working with large objects or nested objects, the spread operator might lead to performance issues.

**Other Alternatives**

If you don't like the spread operator and want an alternative to `Object.assign()`, consider using:

1. **Object.create()**: This method creates a new object with the specified prototype. You can then use the spread operator to merge properties.
2. **Object.keys() + Object.fromEntries()**: This method uses the `keys()` function to get an array of property names and then merges the objects using `fromEntries()`.
3. **Array.prototype.reduce() + Object.assign()**: This method uses `reduce()` to iterate over the properties of one object and merge them into another.

Keep in mind that these alternatives might have slightly different performance characteristics compared to the spread operator and `Object.assign()`.

Related benchmarks:

JavaScript spread operator vs Object.assign performance (same specs) (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):