Benchmark: JavaScript spread operator vs Object.assign performance 1_2

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world', moreData: Math.random() } const secondObject = { sampleData: Math.random(), moreData: 'here we go2' } const finalObject = { ...firstObject, ...secondObject };
Using Object.assign
const firstObject = { sampleData: 'Hello world', moreData: Math.random() } const secondObject = { sampleData: Math.random(), moreData: 'here we go2' } 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:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36 Edg/136.0.0.0

Browser/OS: Chrome 136 on Windows

View result in a separate tab

Test name	Executions per second
Using the spread operator	30676362.0 Ops/sec
Using Object.assign	37955352.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

The provided JSON represents a benchmark test that compares the performance of two approaches to merge two objects in JavaScript: using the spread operator (`...`) and `Object.assign()`.

**Test Case 1: Using the Spread Operator**

In this test case, we have three objects:

* `firstObject`: contains some sample data and a random value for `moreData`.
* `secondObject`: also contains some sample data and a random value for `moreData`, but with different values than in `firstObject`.
* `finalObject`: the merged result of `firstObject` and `secondObject`.

The benchmark definition code is provided inline, which creates these objects and uses the spread operator (`...`) to merge them into `finalObject`.

**Test Case 2: Using Object.assign**

In this test case, we have the same three objects as in Test Case 1. However, instead of using the spread operator, we use the `Object.assign()` method to merge `firstObject` and `secondObject` into `finalObject`.

**Options Compared:**

* **Using the Spread Operator (`...`) vs. Using `Object.assign()`:**
	+ Pros of Using the Spread Operator:
		- More concise and readable code.
		- Less memory allocation, as it creates a new array with references to the original objects' properties.
	+ Cons of Using the Spread Operator:
		- May be slower due to the need for array creation and indexing.
	+ Pros of Using `Object.assign()`: 
		- Generally faster, as it uses native object merge functionality.
	+ Cons of Using `Object.assign()`:
		- Less readable code, especially when dealing with complex objects or nested merges.
		- May allocate more memory due to the creation of a new array-like object.

**Other Considerations:**

* Both approaches have their use cases. The spread operator is often preferred for its conciseness and readability, while `Object.assign()` may be chosen when performance is critical, such as in server-side or high-performance client-side applications.
* In modern JavaScript environments (ECMAScript 2018+), the spread operator is also more efficient due to optimized implementations by browsers like Chrome.

**Library/Features Used:**

None of the provided benchmark definitions use any libraries. However, if you're interested in exploring other options, `Object.assign()` was introduced as a method on the global object (`Object`) in ECMAScript 2015 (ES6).

**Special JS Features/Syntax:**

The spread operator (`...`) is a new feature introduced in ECMAScript 2018. It allows for concise object merging and is enabled by default in modern browsers.

There you have it! The MeasureThat.net benchmark tests the performance of two approaches to merge objects in JavaScript, allowing users to compare the efficiency of these methods.

Related benchmarks:

JavaScript spread operator vs Object.assign performance 1_2 (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

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