# How to Exclude Specific CSS or JS Files from Being Minified by the OpenMage CssjsMinify Module
> Learn how to exclude specific CSS or JS files from minification with OpenMage CssjsMinify. Simply rename files to *.min.* or *.pack.* to automatically skip them without configuration.
- Repository: [Fabrizio Balliano/openmage-cssjs-minify](https://github.com/fballiano/openmage-cssjs-minify)
- Tags: how-to-guide
- Published: 2026-03-01
---
**Rename the files to include `.min.` or `.pack.` in their names (e.g., [`analytics.min.js`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/analytics.min.js) or [`theme.pack.css`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/theme.pack.css)), as the module automatically skips files matching the patterns `*.min.*` or `*.pack.*` without requiring configuration changes.**
The `fballiano/openmage-cssjs-minify` module for OpenMage (Magento 1) automatically minifies CSS and JavaScript files to improve frontend performance. However, if you need to exclude specific CSS or JS files from being minified—perhaps because they are already optimized or break when processed—you must understand how the module's detection logic works, as it does not provide a built-in exclusion list in the admin panel.
## How the Module Detects Already-Minified Files
The minification logic resides in [`app/code/community/Fballiano/CssjsMinify/Model/Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/app/code/community/Fballiano/CssjsMinify/Model/Observer.php). Before processing any asset, the module calls `Fballiano_CssjsMinify_Model_Observer::isAlreadyMinified()` to determine if the file has been pre-minified.
According to the source code in [`Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/Observer.php) (lines 12-15), this method checks the file path against a regular expression:
```php
protected static function isAlreadyMinified($path)
{
return preg_match('/.(min|pack)\.(js|css)$/i', $path);
}
```
If the filename contains `.min.` or `.pack.` before the extension, the method returns `true`, signaling the observer to skip minification.
## The Zero-Code Solution: File Naming Conventions
Because the module lacks a configuration interface for exclusions, the simplest way to exclude specific CSS or JS files from being minified is to rename them to match the detection patterns. When `isAlreadyMinified()` returns true, the observer copies the original file directly to the `fbminify` cache directory without running the minifier.
For JavaScript files referenced in your layout XML or templates:
```html
```
For CSS files:
```html
```
As implemented in [`Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/Observer.php) (lines 48-55 for JS and lines 78-85 for CSS), the logic branches when a match is found, preserving the original file content rather than processing it through the minification engine.
## Creating a Custom Exclusion List via Module Extension
If you need to exclude files based on specific paths rather than naming conventions, you must extend the module, as the base installation does not expose a configuration node for exclusion lists.
First, add a custom configuration section to [`app/code/community/Fballiano/CssjsMinify/etc/config.xml`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/app/code/community/Fballiano/CssjsMinify/etc/config.xml) under the `` node:
```xml
/js/vendor/legacy-library.js/css/admin/unsupported-theme.css
```
Next, modify the `httpResponseSendBefore()` method in [`Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/Observer.php) to read this configuration and skip processing for matching paths:
```php
$excludes = Mage::getStoreConfig('cssjsminify/excludes');
if (is_array($excludes) && in_array($path, $excludes, true)) {
// Return original URL without minification
return $matches[1] . $matches[2] . $matches[3];
}
```
This approach allows you to exclude specific CSS or JS files from being minified based on their full path, even if they do not follow the `.min.` or `.pack.` naming convention.
## Summary
- The `fballiano/openmage-cssjs-minify` module automatically skips files matching `*.min.*` or `*.pack.*` patterns.
- To exclude a file without writing code, rename it to include `.min` or `.pack` before the extension (e.g., [`file.min.js`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/file.min.js)).
- The detection logic is located in `Fballiano_CssjsMinify_Model_Observer::isAlreadyMinified()` in [`Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/Observer.php).
- For path-based exclusions, extend the module by adding configuration in [`config.xml`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/config.xml) and checking it in `httpResponseSendBefore()`.
- Files that match the exclusion patterns are copied to the `fbminify` folder in their original state.
## Frequently Asked Questions
### Does the module provide an admin configuration panel for exclusions?
No, the module does not expose a configuration option for exclusion lists in the OpenMage admin panel. You must either use the file naming convention (`*.min.*` or `*.pack.*`) or extend the module programmatically to add custom exclusion logic.
### What file name patterns will prevent automatic minification?
According to the source code in [`Observer.php`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/Observer.php), the module checks for files ending in [`.min.js`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/.min.js), [`.pack.js`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/.pack.js), [`.min.css`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/.min.css), or [`.pack.css`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/.pack.css) using the regex pattern `/.(min|pack)\.(js|css)$/i`. Any file matching these patterns is considered already minified and is excluded from processing.
### Can I exclude files based on their full path rather than just the file name?
Yes, but this requires custom development. You must add an XML configuration node in [`config.xml`](https://github.com/fballiano/openmage-cssjs-minify/blob/main/config.xml) to store excluded paths, then modify the `httpResponseSendBefore()` observer method to check the current file path against your exclusion list before processing.
### Where does the module store files that are skipped due to naming patterns?
Files that match the exclusion patterns (or are successfully minified) are copied to the `fbminify` folder within your media directory. For skipped files, this is a verbatim copy of the original source, preserving the unminified content while allowing the module to serve it through the same pipeline.