Benchmark: Multiple match calls vs multiple selector fix

HTML Preparation code:

<div class="first"></div>
<div class="second"></div>

Tests:

Multiple match calls
const firstEl = document.querySelector(".first"); const secondEl = document.querySelector(".second"); const array = []; for (let step = 0; step < 5000; step++) { if (firstEl.matches(".first") || firstEl.matches(".second")) { array.push(firstEl); } } for (let step = 0; step < 5000; step++) { if (secondEl.matches(".first") || secondEl.matches(".second")) { array.push(secondEl); } }
Multiple selectors
const firstEl = document.querySelector(".first"); const secondEl = document.querySelector(".second"); const array = []; for (let step = 0; step < 5000; step++) { if (firstEl.matches(".first, .second")) { array.push(firstEl); } } for (let step = 0; step < 5000; step++) { if (secondEl.matches(".first, .second")) { array.push(secondEl); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Multiple match calls
Multiple selectors

Fastest: N/A

Slowest: N/A

Latest run results:

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

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**Overview**

The provided JSON represents two test cases for measuring the performance of JavaScript microbenchmarks on MeasureThat.net. The tests compare different approaches to querying DOM elements using `document.querySelector()`.

**Benchmark Definition and Script Preparation Code**

The benchmark definition is not explicitly provided, but it can be inferred from the individual test cases. Each test case consists of:

1. Creating two `div` elements with classes `.first` and `.second`.
2. Initializing an empty array to store matched elements.
3. Running a loop that iterates 5000 times, checking if each element matches either `.first` or `.second`. If a match is found, the element is pushed into the array.

**Options Compared**

The two options being compared are:

1. **Multiple match calls**: This approach involves calling `matches()` multiple times for each element, like in the first test case: `if (element.matches(" .first") || element.matches(".second"))`.
2. **Single selector with comma-separated values**: This approach involves passing a single string to `matches()` that includes both `.first` and `.second`, like in the second test case: `if (element.matches(" .first, .second"))`.

**Pros and Cons**

**Multiple Match Calls**

Pros:

* Easy to understand and maintain.
* No need to worry about edge cases or incorrect parsing.

Cons:

* Leads to repeated calls to `matches()`, which can be expensive in terms of performance.
* May lead to slower performance due to the overhead of multiple function calls.

**Single Selector with Comma-Separated Values**

Pros:

* Reduces the number of function calls, potentially improving performance.
* Allows for more flexibility in case a new class is added without modifying existing code.

Cons:

* Requires careful parsing of the selector string to ensure correct matches.
* May be harder to understand and maintain for less experienced developers.

**Other Considerations**

* **DOM Traversals**: Both approaches involve traversing the DOM tree. However, the single selector approach might lead to more efficient traversals since it uses a single query instead of separate queries for each element.
* **CSSOM APIs**: The single selector approach relies on the CSSOM API's `matches()` method, which may not be supported by older browsers.

**Library Usage**

None of the tests explicitly use any JavaScript libraries beyond the built-in `document` object and `Array.prototype.push()`. However, it's worth noting that some CSS frameworks or libraries might provide optimized DOM query methods that could potentially affect performance.

**Special JS Features/Syntax**

There is no explicit usage of special JavaScript features or syntax in these tests. The code uses standard ECMAScript 2022 syntax, including template literals and `const` declarations.

In conclusion, the two test cases compare different approaches to querying DOM elements using `document.querySelector()`. While multiple match calls are easy to understand but may lead to slower performance due to repeated function calls, single selectors with comma-separated values offer flexibility and potentially improved performance.

Related benchmarks:

Multiple match calls vs multiple selector fix (version: 0)

Comparing performance of: Multiple match calls vs Multiple selectors

Created: 4 years ago by: Guest

Jump to the latest result

Multiple match calls

Multiple selectors

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):