Benchmark: JavaScript spread operator vs Object.assign performance - fork

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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Let's break down what is tested in the provided JSON and explain the different approaches, pros, cons, and considerations.

**What is being tested?**

The benchmark tests the performance of two ways to merge objects in JavaScript:

1. **Spread Operator (Object Spread Syntax)**: This approach uses the `...` operator to spread the properties of an object onto another object.
2. **Object.assign()**: This built-in method creates a new object by copying all enumerable own properties from one or more source objects into a new object.

**Options compared**

The two approaches being tested are:

* Using the spread operator (`{ ...firstObject, ...secondObject }`)
* Using `Object.assign()` with multiple arguments (`const finalObject = Object.assign({}, firstObject, secondObject)`)

**Pros and Cons of each approach:**

1. **Spread Operator (Object Spread Syntax)**:
	* Pros:
		+ Concise and readable syntax
		+ Easy to understand and use
		+ Faster performance due to its simplicity
	* Cons:
		+ Only available in modern JavaScript environments (ECMAScript 2018+)
		+ May not work as expected in older browsers or environments
2. **Object.assign()**:
	* Pros:
		+ Widely supported across different browsers and environments
		+ Can be used with any number of source objects
	* Cons:
		+ Less concise syntax, requiring multiple function calls or an array of arguments
		+ May have performance overhead due to method call and array creation

**Library:**

There is no library explicitly mentioned in the benchmark definition. However, `Object.assign()` has been a built-in method since ECMAScript 5 (2011), so it's not dependent on any external libraries.

**Special JS feature or syntax:**

The spread operator (`{ ... }`) was introduced in ECMAScript 2018 and is supported by most modern browsers. However, if you need to support older browsers, you may need to use the spread operator polyfill or transpile your code to an earlier version of JavaScript.

**Other alternatives:**

If you prefer not to use the spread operator, you can also merge objects using other methods, such as:

* Using `for...in` loops and manual property assignment
* Using a library like Lodash's `merge()` function
* Creating a custom function for merging objects

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

Related benchmarks:

JavaScript spread operator vs Object.assign performance - fork (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):