Benchmark: JavaScript spread operator vs Object.assign performance (new object)

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

Latest run results:

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

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Let's dive into explaining the JavaScript microbenchmark you provided.

**Benchmark Overview**

The benchmark compares the performance of two approaches to merge two objects: using the spread operator (`...`) and `Object.assign()`. The test case creates three objects: `firstObject`, `secondObject`, and `finalObject`.

**Options Compared**

There are two options being compared:

1. **Using the spread operator**: This approach uses the syntax `{ ...firstObject, ...secondObject }` to merge the two objects. The spread operator (`...`) is used to copy the properties of an object into a new object.
2. **Using `Object.assign()`**: This approach uses the `Object.assign()` method to merge the two objects. It takes two arguments: the target object and an array of source objects.

**Pros and Cons**

1. **Using the spread operator**:
	* Pros:
		+ Concise syntax
		+ Easy to read and understand
		+ Works with modern browsers (ECMAScript 2018)
	* Cons:
		+ May be slower due to the overhead of creating a new array
		+ Limited support in older browsers (pre-ES2015)
2. **Using `Object.assign()`**:
	* Pros:
		+ Faster execution time (due to the optimized implementation in modern browsers)
		+ Wide support across different browsers and versions
	* Cons:
		+ Longer syntax compared to the spread operator
		+ May require more memory allocation

**Library Used**

None is explicitly mentioned. The `Object.assign()` method is a built-in JavaScript method, which means it's part of the standard library.

**Special JS Feature or Syntax**

The spread operator (`...`) was introduced in ECMAScript 2015 (ES6) as a new syntax for spreading array elements into an object. It's also known as the rest parameter syntax.

**Other Considerations**

When deciding between these two approaches, consider the following:

* Performance: If you need to perform this operation frequently, using `Object.assign()` might be faster due to its optimized implementation.
* Code readability and maintainability: The spread operator is generally considered more concise and easier to read, especially for simple cases like this one.
* Browser support: Make sure to test your code across different browsers and versions to ensure compatibility.

**Alternative Approaches**

Some other ways to merge objects in JavaScript include:

1. Using the `merge()` method from libraries like Lodash or Underscore.js
2. Implementing a custom merge function using loops and conditional statements
3. Using a third-party library like ObjectAssign (which is similar to `Object.assign()`)

Related benchmarks:

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

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

Created: 2 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):