Benchmark: JS Object assign vs object new property

Tests:

Object assign
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign(firstObject, secondObject);
Object new property
const firstObject = { sampleData: 'Hello world' } firstObject.moreData = 'foo bar';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object assign
Object new property

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark compares two approaches to assigning values to an object in JavaScript:

1. **`Object.assign()`**: This method creates a new object by copying all own enumerable properties from one or more source objects.
2. **Direct property assignment**: This approach involves assigning values directly to the properties of an existing object.

**Options Compared**

The benchmark compares the performance of these two approaches on the same input data:

* `Object.assign()` with multiple sources (two objects)
* Direct property assignment

**Pros and Cons of Each Approach**

### Object.assign()

Pros:

1. **Convenience**: `Object.assign()` is a convenient way to merge multiple objects into one.
2. **Performance**: In some cases, `Object.assign()` can be faster than direct property assignment due to the optimized implementation in modern browsers.

Cons:

1. **Overhead**: Creating an intermediate object with `Object.assign()` incurs additional overhead compared to direct assignment.
2. **Memory usage**: This approach requires more memory since a new object is created and stored on the heap.

### Direct Property Assignment

Pros:

1. **Efficiency**: Direct property assignment avoids creating an intermediate object, reducing memory allocation and garbage collection overhead.
2. **Low memory footprint**: No additional memory is allocated when using direct assignment.

Cons:

1. **Code complexity**: Using multiple lines of code to assign values directly can make the code harder to read and maintain.

**Other Considerations**

* **Browser support**: Both approaches are supported by modern browsers, but older versions may have limited or no support.
* **Performance optimization**: The benchmark results may not accurately reflect performance in all scenarios. Factors like object size, array length, and property names can affect the outcome.

**Library/Function Used**

None mentioned explicitly, but `Object.assign()` is a built-in JavaScript method used for merging objects.

**Special JS Feature/Syntax**

No special features or syntax are explicitly used in this benchmark. However, it's worth noting that some older browsers may have issues with modern JavaScript features like ES6+ syntax or object assignment methods.

**Alternative Approaches**

Other approaches to assign values to an object might include:

* Using `Array.prototype.concat()` and array destructuring
* Employing a library function for deep merge (e.g., Lodash's `mergeDeep()`)
* Utilizing a third-party utility function for shallow/deep merge

These alternatives may offer different trade-offs in terms of performance, readability, or code complexity.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36

Browser/OS: Chrome 87 on Mac OS X 10.15.2

View result in a separate tab

Test name	Executions per second
Object assign	5766955.0 Ops/sec
Object new property	949564224.0 Ops/sec

Related benchmarks:

JS Object assign vs object new property (version: 0)

Comparing performance of: Object assign vs Object new property

Created: 3 years ago by: Guest

Jump to the latest result

Object assign

Object new property

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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