Benchmark: JavaScript spread operator vs Object.assign performance 2

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world', sample2: false } const secondObject = { moreData: 'foo bar', more2: 4444 } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world', sample2: false } const secondObject = { moreData: 'foo bar', more2: 4444 } 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 Explanation**

The provided benchmark compares the performance of two approaches to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The test creates two sample objects, `firstObject` and `secondObject`, and then attempts to merge them into a new object, `finalObject`.

**Options Compared**

Two options are compared:

1. **Using the spread operator (`...`)**: This approach uses the spread syntax to create a new object by merging the properties of `firstObject` and `secondObject`. The syntax is: `{ ...firstObject, ...secondObject }`.
2. **Using `Object.assign()`**: This approach uses the `Object.assign()` method to merge the properties of two objects into a new object.

**Pros and Cons**

* **Using the spread operator (`...`)**:
	+ Pros:
		- Can be more concise and readable, especially for simple merges.
		- Does not modify the original objects.
	+ Cons:
		- Can be less efficient than `Object.assign()` for large datasets or complex merges.
		- Not supported in older browsers (pre-ES6).
* **Using `Object.assign()`**:
	+ Pros:
		- Widely supported in modern browsers and JavaScript engines.
		- Can handle large datasets and complex merges efficiently.
	+ Cons:
		- May require more code to achieve the same result as using the spread operator.

**Library**

None of the test cases use any libraries, so there are no additional dependencies to consider.

**Special JS Feature/Syntax**

The test case uses ES6 syntax (spread operator and template literals) which is a feature introduced in ECMAScript 2015. This syntax is not supported in older JavaScript engines and browsers, but it's widely adopted in modern development.

**Other Alternatives**

In addition to the spread operator and `Object.assign()`, there are other ways to merge objects in JavaScript:

* **Using the `merge()` method**: Some libraries (e.g., Lodash) provide a `merge()` function that can be used to combine two objects.
* **Using a function**: You can define a custom function to merge two objects, similar to how `Object.assign()` works.

For example:
```javascript
function mergeObjects(obj1, obj2) {
  return Object.keys(obj1).concat(Object.keys(obj2)).reduce((acc, key) => {
    acc[key] = obj1[key] === obj2[key] ? obj1[key] : obj2[key];
    return acc;
  }, {});
}
```
This approach can be more flexible and customizable than using the spread operator or `Object.assign()`, but it may require more code and is less concise.

Related benchmarks:

JavaScript spread operator vs Object.assign performance 2 (version: 0)

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

Created: 7 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):