Benchmark: spread vs assign performance

Tests:

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

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

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Measuring JavaScript performance is an essential task for any developer, and MeasuringThat.net provides a great platform to compare different approaches.

Let's break down what's being tested in this benchmark:

**Benchmark Definition:** The test measures the performance of two approaches: using the spread operator (`...`) and `Object.assign()` methods to merge two objects into a single object.

**Options Compared:**

1. **Using the Spread Operator (`...`)**: This method creates a new object by copying properties from existing objects.
2. **Using `Object.assign()`**: This method assigns values from one or more source objects to a target object, modifying it directly.

**Pros and Cons of Each Approach:**

1. Using the Spread Operator (`...`):
	* Pros:
		+ Creates a new object, which can be beneficial for performance in certain scenarios.
		+ Can lead to better code readability due to its syntax.
	* Cons:
		+ May create unnecessary overhead due to the creation of a new object.
2. Using `Object.assign()`:
	* Pros:
		+ Modifies the target object directly, which can be more efficient in some cases.
	* Cons:
		+ Can lead to slower performance if the resulting object is very large.
		+ May cause issues with code readability and maintainability.

**Library Used:** None

There are no external libraries used in this benchmark.

**Special JS Feature/ Syntax:** The spread operator (`...`) was introduced in ECMAScript 2018 (ES10) and has become a widely adopted feature in modern JavaScript. It allows you to create new objects by copying properties from existing objects.

**Other Alternatives:**

If the spread operator is not an option, other methods can be used to merge objects:

* Using `Array.prototype.reduce()`:
```javascript
const finalObject = {};
Object.keys(firstObject).reduce((acc, key) => {
  acc[key] = firstObject[key];
}, finalObject);
finalObject['...secondObject'] = secondObject;
```
* Using `Object.merge()` (not a built-in method in JavaScript):
```javascript
function Object.merge(obj1, obj2) {
  return Object.assign({}, obj1, obj2);
}

const finalObject = {};
firstObject = Object.merge(finalObject, firstObject);
secondObject = Object.merge(finalObject, secondObject);
```
Keep in mind that these alternatives may have different performance characteristics compared to the spread operator.

In summary, this benchmark provides a simple and straightforward comparison between two approaches to merging objects: using the spread operator (`...`) and `Object.assign()`. The results can help developers understand the trade-offs between these methods and make informed decisions about which approach to use in their own code.

Related benchmarks:

spread vs assign performance (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):