Benchmark: deconst loop - MeasureThat.net

Script Preparation code:

var theArr = Array.from({ length: 10000 }, (_, el) => ({el:el}))
// var theSet = new Set(theArr)
// var theObject = Object.assign({}, ...theArr.map(num => ({ [num]: true })))
// var theMap = new Map(theArr.map(num => [num, true]))

Tests:

deconst
const test = theArr.map(({el}) => el)
without
const test = theArr.map(_el => _el.el)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
deconst
without

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand what's being tested in this JavaScript benchmark.

**Benchmark Overview**

The test case, titled "deconst loop," measures the performance difference between two approaches for extracting values from an array using destructuring syntax. The benchmark defines three scripts:

1. `Script Preparation Code`: This code creates a large array (`theArr`) with 10,000 elements and sets up some optional intermediate variables.
2. `Html Preparation Code`: Not used in this test case.
3. `Benchmark Definition`: Two separate tests, "deconst" and "without", which execute the following mapping function on `theArr`:
	* "deconst": `const test = theArr.map(({el}) => el)`
	* "without": `const test = theArr.map(_el => _el.el)`

**Comparison**

The two tests, "deconst" and "without", are compared to determine which approach is faster. The differences lie in how the destructuring syntax is applied:

1. **Destructuring with an object literal (`{ (el: el) }`)**: This test uses the syntax `({el} => el)` to extract the value `el` from each array element.
2. **Destructuring without an object literal**: This test uses the syntax `_el => _el.el` to directly access the `el` property of each array element.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Destructuring with an object literal (`deconst`)**:
	* Pros:
		+ More explicit and readable code
		+ Can be more efficient for large arrays, as it avoids the overhead of direct property access
	* Cons:
		+ May incur a slight performance penalty due to the additional syntax
2. **Destructuring without an object literal (`without`)**:
	* Pros:
		+ Faster execution, as it directly accesses the `el` property
	* Cons:
		+ Less readable code, especially for developers unfamiliar with destructuring

**Library Usage**

There is no explicit library usage in this benchmark. However, it's worth noting that JavaScript engines like V8 (used by Chrome) have built-in optimizations and syntax analysis capabilities that can affect the performance of these tests.

**Special JS Feature or Syntax**

The benchmark uses the `map()` function, which is a built-in Array method in JavaScript. It also employs destructuring syntax with an object literal (`({el}) => el`), but not with direct property access (`_el => _el.el`). No special features or syntax are used beyond standard JavaScript.

**Other Alternatives**

If you're interested in exploring alternative approaches for similar performance testing, consider the following:

* Using `forEach()` instead of `map()`
* Utilizing `Array.prototype.forEach()` with an arrow function
* Implementing a custom iteration mechanism using loops (e.g., `for...of` or `while`)
* Investigating browser-specific optimizations and polyfills for destructuring and array methods

Related benchmarks:

deconst loop (version: 0)

Comparing performance of: deconst vs without

Created: 3 years ago by: Guest

Jump to the latest result

deconst

without

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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