Benchmark: Object.assign vs spread operator vs set prop vs setPrototypeOf

Tests:

Object.assign
let o = {}, s = {a:0, b:1, c:2} o = Object.assign(s, o)
spread operator
let o = {}, s = {a:0, b:1, c:2} o = {...o, ...s}
set prop
let o = {}, s = {a:0, b:1, c:2} o.a = s.a o.b = s.b o.c = s.c
setPrototypeOf
let o = {}, s = {a:0, b:1, c:2} Object.setPrototypeOf(o, s)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator
set prop
setPrototypeOf

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Linux

View result in a separate tab

Test name	Executions per second
Object.assign	11354919.0 Ops/sec
spread operator	21481918.0 Ops/sec
set prop	1786406784.0 Ops/sec
setPrototypeOf	1322081.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**
The website MeasureThat.net provides a JavaScript microbenchmarking tool. The provided JSON represents a benchmark with four test cases:

* "Object.assign vs spread operator vs set prop vs setPrototypeOf"

This means we're comparing the performance of four different approaches to create an object from scratch or update an existing object:
	1. `Object.assign()`
	2. Spread operator (`{...obj, ...newObj}`)
	3. Setting properties individually (`obj.prop = newObj.prop`)
	4. Setting prototype (`Object.setPrototypeOf(obj, newObj)`)

**Test Cases**
Each test case is defined by a JSON object with the following properties:

* "Benchmark Definition": The JavaScript code to be executed.
* "Test Name": A brief description of the test.

Let's analyze each test case:

1. **`Object.assign(s, o)`**: This approach uses the `Object.assign()` method to merge two objects (`s` and `o`) into a new object. It's a simple and efficient way to create or update an object.
2. **`{...o, ...s}`**: This approach uses the spread operator to create a new object by copying properties from both `o` and `s`. It's another common way to merge objects in JavaScript.
3. **`obj.prop = s.prop; obj.prop2 = s.prop2; ...`**: This approach sets individual properties of the `obj` using the assignment operator (`=`). It can be less efficient than the other two approaches, especially for large numbers of properties.
4. **`Object.setPrototypeOf(o, s)`**: This approach uses the `Object.setPrototypeOf()` method to set the prototype of an object (`o`) to another object (`s`). While not directly creating a new object, this approach can be used to create or update an object's inheritance chain.

**Pros and Cons**

* **`Object.assign(s, o)`**:
	+ Pros: Fast, efficient, and widely supported.
	+ Cons: May not work as expected with objects that have inherited properties.
* **`{...o, ...s}`**:
	+ Pros: Modern, concise syntax, and works well with objects of any depth.
	+ Cons: May be slower than `Object.assign()` due to the overhead of creating a new object via spread operator.
* **`obj.prop = s.prop; obj.prop2 = s.prop2; ...`**:
	+ Pros: Can be used for legacy code or specific use cases where other approaches don't work.
	+ Cons: Less efficient and more verbose than other approaches.
* **`Object.setPrototypeOf(o, s)`**:
	+ Pros: Can be used to create or update an object's inheritance chain, which can be useful in certain scenarios.
	+ Cons: May not directly create a new object, and the prototype setting approach can be less intuitive.

**Library Usage**
There is no explicit library mentioned in the benchmark definition. However, `Object.assign()` and `Object.setPrototypeOf()` rely on the built-in `Object` class, which is part of the JavaScript standard library.

**Special JS Features or Syntax**
None mentioned explicitly.

Related benchmarks:

Object.assign vs spread operator vs set prop vs setPrototypeOf (version: 0)

Comparing performance of: Object.assign vs spread operator vs set prop vs setPrototypeOf

Created: one year ago by: Registered User

Jump to the latest result

Object.assign

spread operator

set prop

setPrototypeOf

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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