Benchmark: Assign once vs destructure twice

Tests:

Assignment
const config = {a: 1, b: 2, item: {show: true}} const itemsToRender = Object.keys(config).filter((item) => config[item].show === true); const numItemsToRender = itemsToRender.length;
Destructuring
const config = {a: 1, b: 2, item: {show: true}} const {length: lengthOfItems} = Object.keys(config).filter((item) => config[item].show === true); const itemsToRender = Object.keys(config).filter((item) => config[item].show === true);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Assignment
Destructuring

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Assignment	7372260.5 Ops/sec
Destructuring	3743939.2 Ops/sec

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

LLMs can make mistakes. Check important info.

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

**Benchmark Definition**

The provided benchmark definition is quite simple, yet it tests two different approaches to achieve the same result. The script preparation code and HTML preparation code are empty, which means that MeasureThat.net will handle these tasks automatically.

The benchmark definition consists of two test cases:

1. **Assignment**: This test case uses a traditional assignment approach, where `itemsToRender` is assigned the result of `Object.keys(config).filter((item) => config[item].show === true);`.
2. **Destructuring**: This test case uses destructuring, where `{length: lengthOfItems}` is assigned to an object literal containing only one property, and then `itemsToRender` is assigned the result of `Object.keys(config).filter((item) => config[item].show === true);`.

**Options Compared**

The two approaches compared are:

1. **Assignment**: This approach involves using the `filter()` method to iterate over an array-like object (`config`) and assign the resulting filtered array to a variable (`itemsToRender`).
2. **Destructuring**: This approach involves using destructuring to extract only the desired property (`lengthOfItems`) from the result of `Object.keys(config).filter((item) => config[item].show === true);`, and then assigning the remaining filtered array to another variable (`itemsToRender`).

**Pros and Cons**

* **Assignment**:
	+ Pros: Simple and straightforward, easy to read and understand.
	+ Cons: May be slower due to the use of `filter()` method, which can lead to unnecessary iterations over the original data structure.
* **Destructuring**:
	+ Pros: Can be faster since it avoids the need for an additional `filter()` call, reducing unnecessary iterations over the data structure. Additionally, destructuring can provide a more concise and readable code form.
	+ Cons: May be less intuitive for developers who are not familiar with destructuring syntax.

**Library**

There is no specific library used in these benchmark definitions. However, it's worth noting that MeasureThat.net itself provides some utility functions to simplify the testing process.

**Special JS Feature or Syntax**

Neither of the provided benchmark definitions uses any special JavaScript features or syntax beyond what's standard in modern JavaScript (ECMAScript 2015+).

**Other Alternatives**

If you were to rewrite these benchmark definitions, you could consider using alternative approaches, such as:

1. Using `for...of` loop instead of `filter()`, which might be more efficient for large datasets.
2. Using a library like Lodash or Ramda, which provide optimized versions of common array operations like filtering.
3. Implementing a custom iterator to avoid unnecessary iterations over the data structure.

Keep in mind that these alternatives would require additional modifications to the benchmark definitions and may impact readability and maintainability.

In conclusion, the provided benchmark definitions test two fundamental approaches to achieve the same result: assignment vs destructuring. While both have their pros and cons, the destructuring approach might be slightly more efficient due to reduced unnecessary iterations over the data structure.

Related benchmarks:

Assign once vs destructure twice (version: 0)

Comparing performance of: Assignment vs Destructuring

Created: 3 years ago by: Guest

Jump to the latest result

Assignment

Destructuring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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