Benchmark: Reflect.set vs Object.assign vs Direct assignment

Script Preparation code:

var numbers = Array(1000).fill(null).map((x, i) => i.toString());

Tests:

Reflect.set
numbers.reduce((acc, n) => Reflect.set(acc, n, n) && acc, {});
Object.assign
numbers.reduce((acc, n) => Object.assign(acc, { [n]: n }), {});
Direct assignment
numbers.reduce((acc, n) => { acc[n] = n; return acc }, {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reflect.set
Object.assign
Direct assignment

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_6_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/131.0.6778.154 Mobile/15E148 Safari/604.1

Browser/OS: Chrome Mobile iOS 131 on iOS 17.6.1

View result in a separate tab

Test name	Executions per second
Reflect.set	42087.9 Ops/sec
Object.assign	228.3 Ops/sec
Direct assignment	31451.9 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 provided JSON data for MeasureThat.net, which measures JavaScript microbenchmarks.

**Benchmark Definition**

The benchmark tests three different approaches to assign values to an object:

1. **Direct assignment**: `numbers.reduce((acc, n) => { acc[n] = n; return acc }, {})`
2. **Reflect.set**: `numbers.reduce((acc, n) => Reflect.set(acc, n, n) && acc, {})`
3. **Object.assign**: `numbers.reduce((acc, n) => Object.assign(acc, { [n]: n }), {})`

**Options Compared**

The three approaches differ in how they assign values to the object:

* **Direct assignment** uses a simple property access (`acc[n] = n`) to set the value of each key.
* **Reflect.set** uses the `Reflect.set` method to dynamically set properties on the object. This method is similar to direct assignment but provides additional features, such as ability to check if a property exists before setting it.
* **Object.assign** uses the `Object.assign` method to merge two objects. In this case, it's used to assign individual values to each key in the source array.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Direct assignment**: Simple and efficient, but may not be suitable for complex assignments or when using existing properties.
	+ Pros: Fast, simple
	+ Cons: May lead to property collisions if keys already exist
* **Reflect.set**: Provides additional features like checking if a property exists before setting it. However, the method is more verbose than direct assignment.
	+ Pros: Flexible, can check for existing properties
	+ Cons: Verbose, may be slower due to dynamic property checks
* **Object.assign**: Easy to use and efficient, but requires creating an object with existing keys first.
	+ Pros: Easy to use, efficient
	+ Cons: Requires extra setup (creating an object with existing keys)

**Library/Feature Usage**

None of the benchmark cases explicitly uses any libraries or special JavaScript features. However, `Reflect.set` is a built-in method in JavaScript's Reflect API.

**Other Considerations**

When choosing between these approaches, consider the specific requirements of your application:

* If simplicity and speed are crucial, direct assignment might be the best choice.
* If flexibility and ability to handle existing properties are necessary, Reflect.set could be a better option.
* If ease of use and performance are key, Object.assign is a good choice.

**Alternative Approaches**

Other alternatives for object assignment in JavaScript include:

* Using `forEach` or `map` with the spread operator (`{...obj}`) to create a new object
* Using a library like Lodash's `assignIn` method to handle nested objects

Keep in mind that these alternatives may have different performance characteristics and use cases compared to the approaches tested in this benchmark.

Related benchmarks:

Reflect.set vs Object.assign vs Direct assignment (version: 0)

Comparing performance of: Reflect.set vs Object.assign vs Direct assignment

Created: 3 years ago by: Guest

Jump to the latest result

Reflect.set

Object.assign

Direct assignment

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):