Benchmark: addEventListener('resize') + innerWidth VS matchMedia() + matchMedia.addEventListener('change')

addEventListener('resize') + innerWidth VS matchMedia() + matchMedia.addEventListener('change') (version: 0)

This benchmark compares using `addEventListener('resize')` with window.innerWidth versus window.matchMedia with it's`addEventListener()` function to see which is faster.

Comparing performance of: matchMedia + addListener vs resize + innerWidth

Created: 2 years ago by: Registered User

Jump to the latest result

HTML Preparation code:

<style>
  #before:before {
  	content: "a";
 	 display: none;
  }
  @media(min-width: 200px) {
  	#body {
  		background: red;
  	content: "b";
  	}
  }
  @media(min-width: 600px) {
  	#body {
  		background: blue;
  	content: "c";
  	}
  }
  @media(min-width: 1000px) {
  	#body {
  		background: yellow;
  	content: "d";
  	}
  }
</style>
<div id="body">
</div>

Tests:

matchMedia + addListener
const matchMedia = window.matchMedia("(min-width: 400px)"); matchMedia.addEventListener('change', event => { if (event.matches) { console.log(true); } })
resize + innerWidth
let currentWidth = window.innerWidth; window.addEventListener('resize', () => { currentWidth = window.innerWidth; }); if (currentWidth > 400) { console.log(true); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
matchMedia + addListener
resize + innerWidth

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 21 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
matchMedia + addListener	203737.1 Ops/sec
resize + innerWidth	864.3 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated 2 months ago):

LLMs can make mistakes. Check important info.

This benchmark compares two ways to detect if the browser window width is larger than 400 pixels:

**Option 1: `matchMedia()` + `addEventListener('change')`:**

*   This approach uses the `window.matchMedia()` function to create a media query object that checks for window width greater than or equal to 400px.  
*   Then, an event listener is added to this object using `addEventListener('change', ...)` which fires whenever the match status of the media query changes (e.g., when the window is resized).

**Option 2: `window.innerWidth` + `addEventListener('resize')`:**

*   This approach directly accesses `window.innerWidth` to get the current width of the browser window.
*   An event listener is added to the `window` object using `addEventListener('resize', ...)` which fires whenever the window size changes.
*   Inside this listener, `window.innerWidth` is checked against 400px and a log statement (likely indicating success) is executed if the condition is met.

**Pros and Cons:**

* **`matchMedia()` + `addEventListener('change')`:**
    * **Pros:** More specific and efficient as it only fires when the media query status changes, potentially saving unnecessary checks. 
    * **Cons:** Requires familiarity with `matchMedia()` and its API.
* **`window.innerWidth` + `addEventListener('resize')`:**
    * **Pros:** Simpler to understand and implement.  
    * **Cons:** Can lead to more frequent event triggers, potentially impacting performance if not handled carefully.

**Other Considerations:**

* **Performance:** While both approaches are generally performant, the benchmark results indicate that `matchMedia()` + `addEventListener('change')` is significantly faster in this specific case.

**Alternatives:**

*   Using a CSS media query and applying dynamic styles based on the width could be an alternative for visual changes rather than relying solely on JavaScript.

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