Benchmark: Object.assing vs spead operator

Tests:

Object.assign
const a = {a: 1, b: 2, c: 3, d(){return 'foo'}, e: [1, 2, 3, 4]}; const b = Object.assign({}, a);
Spread operator
const a = {a: 1, b: 2, c: 3, d(){return 'foo'}, e: [1, 2, 3, 4]} const b = {...a}
Object.assign 2
const a = {a: 1, b: 2, c: 3, d(){return 'foo'}, e: [1, 2, 3, 4]}; const b = {} Object.assign(b, a);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
Spread operator
Object.assign 2

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases to understand what's being tested.

**Benchmark Definition**

The benchmark is defined as "Deep copying an object". This means that the goal of the benchmark is to measure how efficiently JavaScript engines can create a new, independent copy of an object, without modifying the original object.

**Options Compared**

Three options are compared:

1. **Object.assign()**: This method creates a shallow copy of an object by iterating over its enumerable properties and creating new objects for each property.
2. **Spread operator (Object spread syntax)**: This syntax is used to create a new object with the same properties as an existing object, but with new keys. It's a shorthand way of doing Object.assign() with an empty object.
3. **Object.assign() 2**: This option uses a different approach to assign the object being copied to an empty object, which may or may not be relevant to the actual use case.

**Pros and Cons**

Here are some pros and cons for each option:

* **Object.assign()**: Pros: widely supported, well-established. Cons: can lead to shallow copies if not used carefully (i.e., it will only copy own enumerable properties of an object), may not work as expected with non-object values.
* **Spread operator**: Pros: concise, easy to read, and often faster than Object.assign() in modern browsers. Cons: not supported in older browsers or environments, may lead to shallow copies if used with objects that contain functions or other complex values.
* **Object.assign() 2**: This option is likely a variation of the spread operator, but its impact on performance is unclear.

**Library/Feature Used**

None of these options rely on any external libraries. However, modern JavaScript engines may use various internal optimizations to achieve better performance.

**Special JS Feature/Syntax**

The only special syntax used in this benchmark is the spread operator (Object spread syntax), which was introduced in ECMAScript 2015.

**Other Considerations**

This benchmark likely aims to measure how well different browsers and JavaScript engines can perform object copying operations. The results will show which approach is fastest, most efficient, or most scalable for various use cases.

**Alternatives**

If you're looking for alternative benchmarks or testing frameworks, some popular options include:

* Benchmark.js: A high-performance benchmarking library for Node.js.
* jsperf.com: A web-based JavaScript benchmarking platform that allows users to compare different implementation options.
* Google Benchmark: A lightweight, header-only benchmarking library for C++ and other languages.

Keep in mind that the specific requirements and goals of this benchmark may make it less suitable for comparison with these alternatives.

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Browser/OS: Chrome 70 on Linux

View result in a separate tab

Test name	Executions per second
Object.assign	1832163.2 Ops/sec
Spread operator	11505883.0 Ops/sec
Object.assign 2	1853387.1 Ops/sec

Related benchmarks:

Object.assing vs spead operator (version: 0)

Deep copying an object

Comparing performance of: Object.assign vs Spread operator vs Object.assign 2

Created: 6 years ago by: Guest

Jump to the latest result

Object.assign

Spread operator

Object.assign 2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 25 days ago):