Benchmark: Assignt vs spred

Script Preparation code:

var obj = {
    a: 'a',
    b: 'b'
}

Tests:

spred
obj = {...obj, b: 'c'}
assign
obj = Object.assign(obj, {b: 'c'})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spred
assign

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark.

**What is being tested?**

The benchmark is testing the speed difference between two approaches: spread operator (`...`) and `Object.assign()` methods for assigning properties to an object.

**Options compared**

There are two options being compared:

1. **Spread Operator (`...`)**: This approach uses the spread operator to create a new object by spreading the existing object's properties into a new object.
```javascript
obj = {...obj, b: 'c'}
```
2. **`Object.assign()` method**: This approach uses the `Object.assign()` method to assign properties from one or more source objects to a target object.

**Pros and Cons**

**Spread Operator (`...`)**

Pros:

* Shorter and more concise syntax
* Easier to read and understand for many developers
* Fast and efficient since it creates a new object without modifying the original

Cons:

* Not supported in older browsers (before Chrome 42)
* May not work as expected if the spread operator is used with other operators (e.g., `+`, `-`)

**`Object.assign()` method**

Pros:

* Supported by all modern browsers and Node.js
* Can handle assigning properties from multiple source objects
* Works well with other methods, such as `Array.prototype.concat()`

Cons:

* Longer syntax compared to the spread operator
* May be slower than the spread operator since it creates a new object by modifying the original

**Library used**

In this benchmark, no library is explicitly mentioned. However, if you look at the individual test cases, they are using the `Object` constructor and its methods (`assign()`) which are part of the standard JavaScript API.

**Special JS feature or syntax**

The benchmark uses a special feature called **rest parameter syntax**, also known as "spread operator" (e.g., `...obj`). This syntax was introduced in ECMAScript 2015 (ES6) and allows you to pass an arbitrary number of arguments to a function, similar to the way you would use arguments in a traditional function definition. In this benchmark, it's used to spread properties from one object to another.

**Other alternatives**

If you want to explore other approaches for assigning properties to an object, here are some alternatives:

* Using the `Object.assign()` method with an array of key-value pairs: `Object.assign(obj, ['b', 'c'])`
* Using a loop to assign each property individually: `for (var key in obj) { obj[key] = 'c'; }`
* Using a library like Lodash's `assignIn()` function
* Using a functional programming approach with arrow functions and the spread operator

Keep in mind that these alternatives might have different performance characteristics, syntax complexity, or browser support compared to the options being tested in this benchmark.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36

Browser/OS: Chrome 92 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
spred	4792460.5 Ops/sec
assign	5554175.0 Ops/sec

Related benchmarks:

Assignt vs spred (version: 0)

check speed spred and assign

Comparing performance of: spred vs assign

Created: 3 years ago by: Registered User

Jump to the latest result

spred

assign

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):