TailwindFormatter

Enforce a class attribute order within markup using TailwindCSS.

this is a mix format plugin.

Note: The Tailwind Formatter requires Elixir v1.13.4 or later

Installation

Add tailwind_formatter to your list of dependencies in mix.exs:

def deps do
  [
    {:tailwind_formatter, "~> 0.3.0"}

    # alternatively, keep track with the latest release:
    {:tailwind_formatter, github: "100phlecs/tailwind_formatter"}
  ]
end

Setup

Add it as a plugin to your project's .formatter.exs. Make sure to put in the heex extension to the possible inputs.

  [
    plugins: [TailwindFormatter],
    inputs: [
    "*.{heex,ex,exs}",
    "{config,lib,test}/**/*.{heex,ex,exs}"
    ],
  ]

Then run mix deps.get and also mix compile to load in the plugin.

After that, run the formatter with mix format.

Note: If you're using multiple formatters and you're running an Elixir version that supports multiple format plugins, keep in mind that the order by which the plugins are defined in the plugins: [] array are the order in which they are ran.

Setup multiple formatters for older versions

If you plan to use this with another formatter, you may run into issues. Thie is because mix format, depending on your version, may not support multiple plugins (just yet)!

There are two options to work around this. The first option is, if you are formatting with Phoenix.LiveView.HTMLFormatter, to use the MultiFormatter shipped with this library instead of TailwindFormatter.

The MultiFormatter will first format with HTMLFormatter and then follow up with TailwindFormatter.

The other option is to set up two .formatter.exs files and a script within your base directory, i.e. format.sh which runs both.

In format.sh:

#!/usr/bin/env bash
mix format --dot-formatter .tailwind_formatter.exs
mix format # this runs the default .formatter.exs

And then chmod +x format.sh.

Formatting

The formatter aims to follow a bundle of rules outlined in the blog post that introduces the official Tailwind sorter plugin.

Order them the same way classes are imported in the CSS file. Base, Components, Utilities.
Classes that override other classes appear later in the list
Classes that impact layout take precedence over classes that decorate
Plain classes come first before variants (i.e. focus:)
Unknown classes are sorted to the front

How it diverges from the original formatter

There are some differences in order to simplify the algorithm and to support Elixir use cases.

Inline elixir functions are sorted toward the front

With elixir templating one may add an #{inline_elixir_function} to the class list. The formatter supports this and sorts these toward the front.

Variants are always grouped, even if the class is unknown

i.e. sm:unknown-class will still be grouped with the other sm: variants, even if Tailwind doesn't recognize the class.

Variant order is enforced

In the original spec, 'variants' i.e. sm:hover: are sorted as though it is one block. Thus, the order in which they're specified does not matter. So, for example, a chain of dark:sm:hover:text-gray-600 would be placed toward the end.

In this algorithm, classes are sorted by "layers". All sm: variants are grouped together, even if it's a chain of 4 variants. So for example, dark:sm:hover:text-gray-600 will be placed before any sm: and hover: variants, because dark: has precedence over sm: and hover:.

Thus in order to achieve more consistency, the variant chain is ordered. So, dark:sm:hover:text-gray-600 transforms to sm:dark:hover:text-gray-600.

Custom classes

As a bonus this plugin supports the Phoenix variants that ship with new applications.

Otherwise custom classes are not supported at this time. It may be supported in the future.

As this is quite new there may be some Tailwind classes missing.

Credits

This project builds heavily off of rustywind and HTMLFormatter.

zachallaun/tailwind_formatter