Function parseModifier

packages/tailwindcss/src/candidate.ts:615–660

(modifier: string)

}

function parseModifier(modifier: string): CandidateModifier | null {
  if (modifier[0] === '[' && modifier[modifier.length - 1] === ']') {
    let arbitraryValue = decodeArbitraryValue(modifier.slice(1, -1))

    // Values can't contain `;` or `}` characters at the top-level.
    if (!isValidArbitrary(arbitraryValue)) return null

    // Empty arbitrary values are invalid. E.g.: `data-[]:`
    //                                                 ^^
    if (arbitraryValue.length === 0 || arbitraryValue.trim().length === 0) return null

    return {
      kind: 'arbitrary',
      value: arbitraryValue,
    }
  }

  if (modifier[0] === '(' && modifier[modifier.length - 1] === ')') {
    // Drop the `(` and `)` characters
    modifier = modifier.slice(1, -1)

    // A modifier with `(…)` should always start with `--` since it
    // represents a CSS variable.
    if (modifier[0] !== '-' || modifier[1] !== '-') return null

    // Values can't contain `;` or `}` characters at the top-level.
    if (!isValidArbitrary(modifier)) return null

    // Wrap the value in `var(…)` to ensure that it is a valid CSS variable.
    modifier = `var(${modifier})`

    let arbitraryValue = decodeArbitraryValue(modifier)

    return {
      kind: 'arbitrary',
      value: arbitraryValue,
    }
  }

  if (!IS_VALID_NAMED_VALUE.test(modifier)) return null

  return {
    kind: 'named',
    value: modifier,
  }
}

export function parseVariant(variant: string, designSystem: DesignSystem): Variant | null {
  // Arbitrary variants