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 }, {});

Historical Performance Data aggregated from 51 community runs

Desktop Results:

Chrome 36 runs

Direct assignment

131K/s

Reflect.set

10K/s

Object.assign

796/s

Fastest: Direct assignment (164.3x faster)

View exact numbers

✓ Direct assignment: 130,856 ops/sec
• Reflect.set: 9,701 ops/sec
• Object.assign: 796 ops/sec

Firefox 10 runs

Direct assignment

131K/s

Reflect.set

19K/s

Object.assign

893/s

Fastest: Direct assignment (146.4x faster)

View exact numbers

✓ Direct assignment: 130,778 ops/sec
• Reflect.set: 19,057 ops/sec
• Object.assign: 893 ops/sec

Mobile Results:

Chrome 5 runs

Direct assignment

47K/s

Reflect.set

8K/s

Object.assign

311/s

Fastest: Direct assignment (152.4x faster)

View exact numbers

✓ Direct assignment: 47,459 ops/sec
• Reflect.set: 7,670 ops/sec
• Object.assign: 311 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

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: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0

Browser/OS: Firefox 137 on Windows

View result in a separate tab

Direct assignment

89K/s

Reflect.set

10K/s

Object.assign

519/s

View exact numbers

Test name	Executions per second
✓ Direct assignment	88,606 Ops/sec
Reflect.set	10,343 Ops/sec
Object.assign	519 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year 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.

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

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

Created: 5 years ago by: Guest

Go to the latest result

Reflect.set

Object.assign

Direct assignment

Historical Performance Data aggregated from 51 community runs

Desktop Results:

Chrome 36 runs

Firefox 10 runs

Mobile Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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

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

Created: 5 years ago by: Guest

Go to the latest result

Reflect.set

Object.assign

Direct assignment

Historical Performance Data aggregated from 51 community runs

Desktop Results:

Chrome 36 runs

Firefox 10 runs

Mobile Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

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