prettier-plugin-classnames/README.md

A Prettier plugin that wraps verbose class name based on the `printWidth` option.

# prettier-plugin-classnames

A Prettier plugin that wraps verbose class name based on the `printWidth` option.

![A use case for this plugin.](.github/banner.png)

## Installation

For Prettier v2:

```sh
npm install -D prettier@^2 prettier-plugin-classnames
```

For Prettier v3:[^1]

```sh
npm install -D prettier prettier-plugin-classnames
```

[^1]: If your version of `prettier-plugin-classnames` is less than `0.4.0`, you will also need to install `@prettier/sync`.

## Configuration

JSON example:

```json
{
  "plugins": ["prettier-plugin-classnames"]
}
```

JS example (CommonJS module):

```javascript
module.exports = {
  plugins: ['prettier-plugin-classnames'],
  customAttributes: ['myClassProp'],
  customFunctions: ['clsx'],
};
```

JS example (ES module):

```javascript
export default {
  plugins: ['prettier-plugin-classnames'],
  endingPosition: 'absolute',
};
```

## Options

### Custom Attributes

List of attributes that enclosing class names.<br>
The `class` and `className` attributes are always supported, even if no options are specified.

<!-- prettier-ignore -->
Default | CLI&nbsp;Override | API&nbsp;Override
--- | --- | ---
`[]` | `--custom-attributes <string>` | `customAttributes: ["<string>"]`

### Custom Functions

List of functions that enclosing class names.<br>
The `classNames` function is always supported, even if no options are specified.

<!-- prettier-ignore -->
Default | CLI&nbsp;Override | API&nbsp;Override
--- | --- | ---
`[]` | `--custom-functions <string>` | `customFunctions: ["<string>"]`

### Ending Position

First available in v0.5.0.

This is the criterion for ending the class name on each line when replacing the original class name with a multi-line class name.

- `relative` example:

  ```
  --------------------------------------------------| printWidth=50
  export function Callout({ children }) {
    return (
      <div
                  |--------------------------------------------------|
        className="bg-gray-100/50 border border-zinc-400/30
         |--------------------------------------------------|
          dark:bg-neutral-900/50 dark:border-neutral-500/30
          px-4 py-4 rounded-xl"
      >
        {children}
      </div>
    );
  }
  ```

- `absolute` example:

  ```
  --------------------------------------------------| printWidth=50
  export function Callout({ children }) {
    return (
      <div
        className="bg-gray-100/50 border
  border-zinc-400/30 dark:bg-neutral-900/50
  dark:border-neutral-500/30 px-4 py-4 rounded-xl"
      >
        {children}
      </div>
    );
  }
  ```

- `absolute-with-indent` (first available in v0.6.0) example:

  ```
  --------------------------------------------------| printWidth=50
  export function Callout({ children }) {
    return (
      <div
        className="bg-gray-100/50 border
          border-zinc-400/30 dark:bg-neutral-900/50
          dark:border-neutral-500/30 px-4 py-4
          rounded-xl"
      >
        {children}
      </div>
    );
  }
  ```

<!-- prettier-ignore -->
Default | CLI&nbsp;Override | API&nbsp;Override
--- | --- | ---
`"relative"` | `--ending-position <relative\|absolute\|absolute-with-indent>` | `endingPosition: "<relative\|absolute\|absolute-with-indent>"`

### Experimental Optimization

First available in v0.7.2.

Formatting will be up to 67% faster. Note that Node.js version must be 17 or higher, and the output of nested expressions may be slightly different.

<!-- prettier-ignore -->
Default | CLI&nbsp;Override | API&nbsp;Override
--- | --- | ---
`false` | `--experimental-optimization` | `experimentalOptimization: <boolean>`

### Syntax Transformation

First available in v0.7.7.

If a line wrapping occurs in a class name written in non-expression syntax, it is transformed into expression syntax. This transformation does not support reversible formatting.

<!-- prettier-ignore -->
Default | CLI&nbsp;Override | API&nbsp;Override
--- | --- | ---
`false` | `--syntax-transformation` | `syntaxTransformation: <boolean>`

## Version correlation with sibling plugins

Starting with `0.6.0`, when there is a minor release on one side, I plan to reflect that change on the other side as well if possible.

![Version correlation.](.github/correlation.png)

## Compatibility with other Prettier plugins

If more than one Prettier plugin can handle the text you want to format, Prettier will only use the last of those plugins.

In this case, you can configure it as follows by adding [prettier-plugin-merge](https://github.com/ony3000/prettier-plugin-merge) to apply those plugins sequentially.

JSON example:

<!-- prettier-ignore -->
```json
{
  "plugins": [
    "prettier-plugin-tailwindcss",
    "prettier-plugin-classnames",
    "prettier-plugin-merge"
  ]
}
```