Benchmark: JavaScript spread operator vs Object.assign performance vs. Native Assignment

Tests:

Using the spread operator
const firstObject = { sampleData: 'Hello world' }; const secondObject = { moreData: 'foo bar' }; const finalObject = { ...firstObject, ...secondObject };
AخA

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);
const firstObject = { sampleData: 'Hello world' };
const secondObject = { moreData: 'foo bar' };
const finalObject = Object.assign(firstObject, secondObject);
Using Native assignment.
const firstObject = { sampleData: 'Hello world' }; const secondObject = { moreData: 'foo bar' }; firstObject.moreData = 'foo bar';
const firstObject = { sampleData: 'Hello world' };
const secondObject = { moreData: 'foo bar' };
firstObject.moreData = 'foo bar';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
Using the spread operator
Using Object.assign
Using Native assignment.

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.92 Safari/537.36

Browser/OS: Chrome 69 on Mac OS X 10.12.6

View result in a separate tab

Test name	Executions per second
Using the spread operator	2381782.8 Ops/sec
Using Object.assign	3596641.8 Ops/sec
Using Native assignment.	352089024.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 4 months ago):

Let's dive into the benchmark.

Benchmark Overview

The benchmark compares the performance of three ways to merge objects in JavaScript: using the spread operator (...), Object.assign(), and native assignment (firstObject.moreData = 'foo bar';). The goal is to determine which approach is the fastest.

Options Compared

Using the spread operator (...):
- Pros: Modern and concise syntax, easy to read and write.
- Cons: May incur additional overhead due to the creation of a new object or array.
Using Object.assign():
- Pros: Standardized and widely supported, can handle more complex data merging scenarios.
- Cons: Can be slower than native assignment for simple cases, has a higher memory footprint.
Native Assignment (firstObject.moreData = 'foo bar';):
- Pros: Fastest execution time among the three options, has the lowest memory overhead.
- Cons: Non-standard syntax, may not be readable or maintainable for complex cases.

Library Usage

There is no explicit library usage in the benchmark definition. However, it's worth noting that Object.assign() relies on the Object.prototype property, which might not be the case in all browsers or environments.

Special JavaScript Features/Syntax

None mentioned in the provided data.

Other Considerations

The benchmark uses a fixed number of objects to merge (firstObject and secondObject), which may not accurately represent real-world scenarios where objects have different structures and properties.
The benchmark only tests simple assignment of a string value, ignoring more complex merging cases like array or object property updates.

Alternatives

Other alternatives for merging objects in JavaScript include:

Lodash's merge() function
Ramda's merge function
JSON merge libraries like json-merge or json-migrate

These alternatives may offer different performance profiles, syntaxes, and feature sets compared to the options tested in this benchmark.

LLMs can make mistakes. Check important info.

Let's dive into the benchmark.

**Benchmark Overview**

The benchmark compares the performance of three ways to merge objects in JavaScript: using the spread operator (`...`), `Object.assign()`, and native assignment (`firstObject.moreData = 'foo bar';`). The goal is to determine which approach is the fastest.

**Options Compared**

1. **Using the spread operator (`...`)**:
	* Pros: Modern and concise syntax, easy to read and write.
	* Cons: May incur additional overhead due to the creation of a new object or array.
2. **Using `Object.assign()`**:
	* Pros: Standardized and widely supported, can handle more complex data merging scenarios.
	* Cons: Can be slower than native assignment for simple cases, has a higher memory footprint.
3. **Native Assignment (`firstObject.moreData = 'foo bar';`)**:
	* Pros: Fastest execution time among the three options, has the lowest memory overhead.
	* Cons: Non-standard syntax, may not be readable or maintainable for complex cases.

**Library Usage**

There is no explicit library usage in the benchmark definition. However, it's worth noting that `Object.assign()` relies on the `Object.prototype` property, which might not be the case in all browsers or environments.

**Special JavaScript Features/Syntax**

None mentioned in the provided data.

**Other Considerations**

* The benchmark uses a fixed number of objects to merge (`firstObject` and `secondObject`), which may not accurately represent real-world scenarios where objects have different structures and properties.
* The benchmark only tests simple assignment of a string value, ignoring more complex merging cases like array or object property updates.

**Alternatives**

Other alternatives for merging objects in JavaScript include:

* Lodash's `merge()` function
* Ramda's `merge` function
* JSON merge libraries like json-merge or json-migrate

These alternatives may offer different performance profiles, syntaxes, and feature sets compared to the options tested in this benchmark.

Related benchmarks:

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

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

Created: 6 years ago by: Guest

Jump to the latest result

Using the spread operator

Using Object.assign

Using Native assignment.

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 4 months ago):