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Prettier for XML

@prettier/plugin-xml is a prettier plugin for XML. prettier is an opinionated code formatter that supports multiple languages and integrates with most editors. The idea is to eliminate discussions of style in code review and allow developers to get back to thinking about code design instead.

Getting started

To run prettier with the XML plugin, you're going to need node.

If you're using the npm CLI, then add the plugin by:

npm install --save-dev prettier @prettier/plugin-xml

Or if you're using yarn, then add the plugin by:

yarn add --dev prettier @prettier/plugin-xml

The prettier executable is now installed and ready for use:

./node_modules/.bin/prettier --write '**/*.xml'

Configuration

Below are the options (from src/plugin.ts) that @prettier/plugin-xml currently supports:

API Option	CLI Option	Default	Description
`bracketSameLine`	`--bracket-same-line`	`true`	Same as in Prettier (see prettier docs)
`printWidth`	`--print-width`	`80`	Same as in Prettier (see prettier docs).
`singleAttributePerLine`	`--single-attribute-per-line`	`false`	Same as in Prettier (see prettier docs)
`tabWidth`	`--tab-width`	`2`	Same as in Prettier (see prettier docs).
`xmlSelfClosingSpace`	`--xml-self-closing-space`	`true`	Adds a space before self-closing tags.
`xmlWhitespaceSensitivity`	`--xml-whitespace-sensitivity`	`"strict"`	Options are `"strict"` and `"ignore"`. You may want `"ignore"`, see below.

Any of these can be added to your existing prettier configuration file. For example:

{
  "tabWidth": 4
}

Or, they can be passed to prettier as arguments:

prettier --tab-width 4 --write '**/*.xml'

Whitespace

In XML, by default, all whitespace inside elements has semantic meaning. For prettier to maintain its contract of not changing the semantic meaning of your program, this means the default for xmlWhitespaceSensitivity is "strict". When running in this mode, prettier's ability to rearrange your markup is somewhat limited, as it has to maintain the exact amount of whitespace that you input within elements.

If you're sure that the XML files that you're formatting do not require whitespace sensitivity, you can use the "ignore" option, as this will produce a standardized amount of whitespace. This will fix any indentation issues, and collapse excess blank lines (max of 1 blank line). For most folks most of the time, this is probably the option that you want.

Ignore ranges

You can use two special comments to get prettier to ignore formatting a specific piece of the document, as in the following example:

<foo>
  <!-- prettier-ignore-start -->
    <this-content-will-not-be-formatted     />
  <!-- prettier-ignore-end -->
</foo>

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/prettier/plugin-xml.

License

The package is available as open source under the terms of the MIT License.

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