Benchmark: JavaScript spread operator vs Object.assign performance samba

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:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Using the spread operator	41180096.0 Ops/sec
Using Object.assign	10265569.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Benchmark Definition JSON**

The benchmark definition is not explicitly provided, but we can infer its purpose by looking at the individual test cases.

The benchmark appears to be measuring the performance of two different methods for merging objects in JavaScript:

1. Using the spread operator (e.g., `const finalObject = { ...firstObject, ...secondObject }`)
2. Using `Object.assign()` (e.g., `const finalObject = Object.assign({}, firstObject, secondObject)`)

**Test Cases**

There are two individual test cases, each with its own benchmark definition and a unique name:

1. **Using the spread operator**: This test case uses the spread operator to merge two objects, `firstObject` and `secondObject`, into a new object, `finalObject`.
2. **Using Object.assign**: This test case uses the `Object.assign()` method to merge two objects, `firstObject` and `secondObject`, into a new object, `finalObject`.

**Options Compared**

The two options being compared are:

* Using the spread operator (e.g., `{ ...firstObject, ...secondObject }`)
* Using `Object.assign()` (e.g., `Object.assign({}, firstObject, secondObject)`)

**Pros and Cons of Each Approach**

Here's a brief summary of the pros and cons of each approach:

**Using the Spread Operator:**

Pros:

* More concise and readable code
* Easier to understand and maintain
* Can be faster due to fewer function calls

Cons:

* May require more compiler optimizations or browser support
* Can lead to memory leaks if not used carefully

**Using Object.assign():**

Pros:

* Widely supported across browsers and Node.js versions
* Familiar interface for developers who have used other languages with similar methods (e.g., Java's `Object.assign()`)

Cons:

* Less concise and less readable code compared to the spread operator
* May be slower due to more function calls

**Library Usage**

None of the test cases explicitly use any libraries, but we can assume that the JavaScript engine being tested is a modern one that supports both the spread operator and `Object.assign()`.

**Special JS Feature or Syntax**

There doesn't seem to be any special JS feature or syntax used in these benchmark test cases. Both methods are standard and widely supported.

**Other Alternatives**

If you need to merge objects in JavaScript, there are a few other alternatives:

* Using the `merge()` function from the Lodash library
* Using the `Object.merge()` method (not widely supported)
* Using the `assignIn()` method (a more concise version of `Object.assign()`)
* Creating a custom merging function using object iteration and concatenation

Keep in mind that performance differences between these methods may be small or negligible, depending on the specific use case and JavaScript engine being used.

Related benchmarks:

JavaScript spread operator vs Object.assign performance samba (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):