Prettier for Melody

This Plugin enables Prettier to format .twig files, as well as .html.twig and .melody.twig. Melody is a component based UI framework that uses Twig as its template language.

Recent Improvements

Version 2.2.2 🚀

This version focuses on core Twig functionality:

🎯 Focused Approach

• Pure Twig formatting: Focused on core Twig template formatting without CSS-specific features
• Simplified codebase: Removed complex integrations to maintain plugin reliability
• Better performance: Reduced overhead by removing unnecessary processing
• Enhanced compatibility: Better compatibility with other formatting tools

Version 2.2.1

This version fixes the performance regression introduced in 2.2.0:

⚡ Performance Fix

• FIXED: Performance regression: Removed subprocess-based Tailwind sorting that caused 30+ second formatting times
• Restored performance: Back to ~1 second formatting time for large files
• Simplified implementation: Focus on core functionality without performance overhead

Version 2.2.0

This version included critical Tailwind CSS compatibility bug fixes:

🐛 Critical Bug Fixes

• Fixed hover pseudo-class bug: No more hoverdata-vue-alpine-X attributes replacing hover: classes
• Preserved all CSS pseudo-classes: hover:, focus:, active:, disabled:, sm:, md:, etc. are now correctly preserved
• Compatible with Tailwind CSS: Works seamlessly alongside prettier-plugin-tailwindcss when both plugins are configured

⚡ Performance & Compatibility

• High performance: No performance impact on formatting speed
• Backwards compatible: All existing functionality preserved
• Production ready: Handles complex templates with mixed Twig/Vue.js/Alpine.js/Tailwind syntax

Version 1.0.5

Previous enhancements for modern frontend development:

🎯 Vue.js & Alpine.js Integration

• Full directive support: All Vue.js and Alpine.js directives are now properly recognized and formatted
• Smart v-pre handling: Content inside v-pre elements is preserved exactly as written, with support for any HTML element
• Template expression protection: Vue.js template expressions (${ ... }) are protected from line breaks to prevent JavaScript compilation errors
• Future-proof element detection: Uses intelligent regex patterns instead of hardcoded element lists

Install

yarn add --dev @rawwee/prettier-plugin-twig-melody

Use

prettier --write "**/*.melody.twig"

In your editor, if the plugin is not automatically picked up and invoked (e.g., if you are using format on save, but no formatting is happening when you save), try adding the plugin explicitly in your Prettier configuration (e.g., .prettierrc.json) using the plugins key:

{
    "printWidth": 80,
    "tabWidth": 4,
    "plugins": ["@sanderjn/prettier-plugin-twig-melody"]
}

Options

This Prettier plugin comes with some options that you can add to your Prettier configuration (e.g., prettierrc.json).

twigSingleQuote (default: true)

Values can be true or false. If true, single quotes will be used for string literals in Twig files.

twigMelodyPlugins (default: [])

An array containing file paths to plugin directories. This can be used to add your own printers and parser extensions.

The paths are relative paths, seen from the project root. Example:

"twigMelodyPlugins": ["src-js/some-melody-plugin", "src-js/some-other-plugin"]

twigPrintWidth (default: 80)

Because Twig files might have a lot of nesting, it can be useful to define a separate print width for Twig files. This can be done with this option. If it is not set, the standard printWidth option is used.

twigAlwaysBreakObjects (default: false)

If set to true, objects will always be wrapped/broken, even if they would fit on one line:

<section
    class="{{ {
    base: css.prices
} | classes }}"
></section>

If set to false (default value), this would be printed as:

<section class="{{ { base: css.prices } | classes }}"></section>

twigFollowOfficialCodingStandards (default: true)

Follow the standards described in https://twig.symfony.com/doc/2.x/coding_standards.html exactly. If set to false, some slight deviations might occur, such as spaces around the filter | operator (s | upper instead of s|upper).

twigOutputEndblockName (default: false)

Choose whether to output the block name in {% endblock %} tags (e.g., {% endblock content %}) or not. The default is not to output it.

twigMultiTags (default: [])

An array of coherent sequences of non-standard Twig tags that should be treated as belonging together. Example (inspired by Craft CMS):

twigMultiTags: [
    "nav,endnav",
    "switch,case,default,endswitch",
    "ifchildren,endifchildren",
    "cache,endcache"
]

Looking at the case of nav,endnav, this means that the Twig tags {% nav %} and {% endnav %} will be treated as a pair, and everything in between will be indented:

{% nav entry in entries %}
    <li>
        <a href="{{ entry.url }}">{{ entry.title }}</a>
    </li>
{% endnav %}

If we did not list the "nav,endnav" entry in twigMultiTags, this code example would be printed without indentation, because {% nav %} and {% endnav %} would be treated as unrelated, individual Twig tags:

{% nav entry in entries %}
<li>
    <a href="{{ entry.url }}">{{ entry.title }}</a>
</li>
{% endnav %}

Note that the order matters: It has to be "nav,endnav", and it must not be "endnav,nav". In general, the first and the last tag name matter. In the case of "switch,case,default,endswitch", the order of case and default does not matter. However, switch has to come first, and endswitch has to come last.

CSS Framework Compatibility

This plugin focuses on Twig template formatting and works well alongside CSS formatting tools. For Tailwind CSS class sorting, we recommend using prettier-plugin-tailwindcss separately on your HTML/CSS files.

The Original Issue (Fixed in v2.2.0)

Previously, this plugin had a bug where CSS pseudo-classes like hover:, focus:, etc. were incorrectly transformed into invalid attributes like hoverdata-vue-alpine-0.

This is now fixed:

<!-- Input and Output (correctly preserved) -->
<div class="hover:bg-gray-100 focus:outline-none">

Multi-Plugin Setup

You can use this plugin alongside other formatting tools:

{
    "plugins": ["@sanderjn/prettier-plugin-twig-melody"],
    "overrides": [
        {
            "files": "*.twig",
            "options": {
                "parser": "melody"
            }
        }
    ]
}

Features

Vue.js and Alpine.js Support

This plugin provides comprehensive support for Vue.js and Alpine.js directives when used in Twig templates, making it perfect for modern frontend frameworks integrated with Twig.

Supported Vue.js Directives

All Vue.js directives are fully supported and properly formatted:

• Basic directives: v-model, v-show, v-if, v-else, v-for, v-html, v-text
• Event handlers: v-on:click, v-on:submit, @click, @submit
• Attribute binding: v-bind:class, v-bind:style, :class, :style, :href
• Modifiers: v-model.lazy, v-on:click.prevent, @keyup.enter
• Custom directives: Any directive following Vue.js naming conventions

Special v-pre Directive Handling

The v-pre directive receives special treatment to preserve raw content exactly as written:

<!-- Content inside v-pre is preserved exactly as-is -->
<div v-pre>
    {{ raw_content_not_processed }}
    <span   class="preserve-spacing"   >{{ unformatted }}</span>
    {% if condition %}Raw Twig syntax preserved{% endif %}
</div>

<!-- Regular content is formatted normally -->
<div>
    {{ formatted_content }}
    <span class="normalized-spacing">{{ processed }}</span>
    {% if condition %}
        Formatted Twig syntax
    {% endif %}
</div>

Vue.js Template Expression Protection

Vue.js template expressions (${ ... }) are automatically protected from line breaks to prevent JavaScript compilation errors:

<!-- This problematic expression is automatically fixed -->
<span>${ car.field_compareModelRemoveTitleSpace == true ? car.title : ' ' + car.title }</span>

<!-- Expressions remain on single lines for valid JavaScript -->
<span>${car.field_compareModelRemoveTitleSpace == true ? car.title : ' ' + car.title}</span>

Alpine.js Directives

All Alpine.js directives are supported with proper formatting:

• Basic directives: x-data, x-show, x-if, x-for, x-html, x-text
• Event handlers: x-on:click, @click, @submit
• Attribute binding: x-bind:class, :class, :style
• Modifiers: x-on:click.prevent, @keyup.enter

Smart Element Detection

The plugin uses intelligent regex patterns to support:

• All standard HTML elements (div, span, input, button, etc.)
• HTML5 semantic elements (article, section, figure, details, etc.)
• Custom elements (my-component, custom-element, etc.)
• Any valid HTML element name pattern (future-proof)

prettier-ignore and prettier-ignore-start

When you are not happy with how Prettier formats a certain element or section in the code, you can tell it to leave it in peace:

{# prettier-ignore #}
<div   class="weird-formatting"   >This will not be re-formatted</div>

<div   class="weird-formatting"   >But this will be</div>

You can also tell Prettier to leave entire regions as they are:

{# prettier-ignore-start #}
    ...
{# prettier-ignore-end #}

Plugins

Melody features an extensible parser, so chances are you add custom elements for which the parsing and printing logic is not part of this Prettier plugin. Therefore, this Prettier plugin is itself pluggable.

Let's look at an example of a plugin to the plugin:

const melodyIconPlugin = require("../melody-plugin-icon-tag");

const printIconTag = (node, path, print, options) => {
    // Implementation of printing
    // ...
};

module.exports = {
    melodyExtensions: [melodyIconPlugin],
    printers: {
        IconTag: printIconTag
    }
};

As we can see, a plugin to the plugin exports two fields:

• melodyExtensions: A list of extensions to the Melody framework that might export tags, visitors, functionMap and the like. Usually, such an extension will add additional parsing functionality to the core parser.
• printers: The Prettier printing functionality for your additional language constructs, tags, operators, etc. This is an object where the keys are the node types in the Melody AST (abstract syntax tree) — as retrieved through node.constructor.name —, and the values are the print functions with the standard Prettier signature.

Don't forget to make your plugins known through the twigMelodyPlugins option in your Prettier configuration.

Testing

• You can call yarn test to test against all regular tests