no-arbitrary-value.md

Forbid using arbitrary values in classnames (no-arbitrary-value)

Tailwind CSS 3 is Just In Time, all the time. It brings flexibility, great compilation perfs and arbitrary values. Arbitrary values are great but can be problematic too if you wish to restrict developer to stick with the values defined in the Tailwind CSS config file.

By default this rule is turned off, if you want to use it set it to warn or error.

Rule Details

Examples of incorrect code for this rule:

<div class="border-[4px]">border width</div>

Examples of correct code for this rule:

<div class="border-4">border width</div>

Options

...
"tailwindcss/no-arbitrary-value": [<enabled>, {
  "callees": Array<string>,
  "config": <string>|<object>,
  "skipClassAttribute": <boolean>,
  "tags": Array<string>,
}]
...

callees (default: ["classnames", "clsx", "ctl", "cva", "tv"])

If you use some utility library like @netlify/classnames-template-literals, you can add its name to the list to make sure it gets parsed by this rule.

For best results, gather the declarative classnames together, avoid mixing conditional classnames in between, move them at the end.

ignoredKeys (default: ["compoundVariants", "defaultVariants"])

Using libraries like cva, some of its object keys are not meant to contain classnames in its value(s). You can specify which key(s) won't be parsed by the plugin using this setting. For example, cva has compoundVariants and defaultVariants. NB: As compoundVariants can have classnames inside its class property, you can also use a callee to make sure this inner part gets parsed while its parent is ignored.

config (default: generated by tailwindcss/lib/lib/load-config)

By default the plugin will try to load the file returned by the official loadConfig() utility.

This allows the plugin to use your customized colors, spacing, screens...

You can provide another path or filename for your Tailwind CSS config file like "config/tailwind.js".

If the external file cannot be loaded (e.g. incorrect path or deleted file), an empty object {} will be used instead.

It is also possible to directly inject a configuration as plain object like { prefix: "tw-", theme: { ... } }.

Finally, the plugin will merge the provided configuration with Tailwind CSS's default configuration.

skipClassAttribute (default: false)

Set skipClassAttribute to true if you only want to lint the classnames inside one of the callees. While, this will avoid linting the class and className attributes, it will still lint matching callees inside of these attributes.

tags (default: [])

Optional, if you are using tagged templates, you should provide the tags in this array.

classRegex (default: "^class(Name)?$")

Optional, can be used to support custom attributes

Further Reading

This rule will not fix the issue for you because it cannot guess the correct class candidate.