Benchmark: JavaScript spread operator with dirty object

Tests:

Common object
const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };
Dirty object
Object.prototype.a = 5; Object.prototype.a = 6; Object.prototype.a = 7; const firstObject = { sampleData: 'Hello world' } const secondObject = { moreData: 'foo bar' } const finalObject = { ...firstObject, ...secondObject };

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Common object
Dirty object

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Windows

View result in a separate tab

Test name	Executions per second
Common object	1463330.5 Ops/sec
Dirty object	739260.4 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**

The benchmark is designed to measure the performance of JavaScript's spread operator (`...`) in creating new objects by merging two existing objects. The test cases are:

1. **Common object**: This test case creates a new object `finalObject` by spreading the properties of `firstObject` and `secondObject`.
2. **Dirty object**: This test case also merges two objects, but it first assigns values to `Object.prototype.a` in each iteration.

**Options being compared**

The benchmark compares the performance of creating a new object using the spread operator (`...`) with two different approaches:

1. **Common object**: Spreading the properties of `firstObject` and `secondObject` directly.
2. **Dirty object**: Assigning values to `Object.prototype.a` in each iteration, followed by spreading the properties.

**Pros and Cons**

* **Common object**:
	+ Pros: Simple and straightforward approach, easy to understand and maintain.
	+ Cons: May not be optimized for performance, as it involves creating multiple objects with similar properties.
* **Dirty object**:
	+ Pros: Can potentially optimize performance by reusing the `Object.prototype.a` assignment in each iteration.
	+ Cons: More complex and harder to understand, especially when debugging.

**Libraries and special JS features**

Neither test case uses a library or any special JavaScript feature. The benchmark only relies on built-in JavaScript features.

**Other considerations**

When interpreting the benchmark results, consider the following:

* **ExecutionsPerSecond**: This metric measures the number of iterations performed per second. A higher value indicates better performance.
* **TestName**: Each test case has a unique name, allowing users to easily compare and analyze different scenarios.

**Alternatives**

Other alternatives for creating new objects by merging two existing objects include:

1. **Object.assign()**: This method is similar to the spread operator but returns the destination object, which might affect performance in certain scenarios.
2. **Object.create()**: This method creates a new object with a given prototype and initializes its properties using an object initializer function.

Keep in mind that the choice of approach depends on specific use cases and requirements. The benchmark results provided by MeasureThat.net can help users choose the most efficient approach for their particular scenario.

Related benchmarks:

JavaScript spread operator with dirty object (version: 0)

Comparing performance of: Common object vs Dirty object

Created: 4 years ago by: Guest

Jump to the latest result

Common object

Dirty object

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):