parse() — tailwindcss Function Reference

Source Code

packages/tailwindcss/src/css-parser.ts lines 64–594

export function parse(input: string, opts?: ParseOptions) {
  let source: Source | null = opts?.from ? { file: opts.from, code: input } : null

  // Note: it is important that any transformations of the input string
  // *before* processing do NOT change the length of the string. This
  // would invalidate the mechanism used to track source locations.
  if (input[0] === '\uFEFF') input = ' ' + input.slice(1)

  let ast: AstNode[] = []
  let licenseComments: Comment[] = []

  let stack: (Rule | null)[] = []

  let parent = null as Rule | null
  let node = null as AstNode | null

  let buffer = ''
  let closingBracketStack = ''

  // The start of the first non-whitespace character in the buffer
  let bufferStart = 0

  let peekChar

  for (let i = 0; i < input.length; i++) {
    let currentChar = input.charCodeAt(i)

    // Skip over the CR in CRLF. This allows code below to only check for a line
    // break even if we're looking at a Windows newline. Peeking the input still
    // has to check for CRLF but that happens less often.
    if (currentChar === CARRIAGE_RETURN) {
      peekChar = input.charCodeAt(i + 1)
      if (peekChar === LINE_BREAK) continue
    }

    // Current character is a `\` therefore the next character is escaped,
    // consume it together with the next character and continue.
    //
    // E.g.:
    //
    // ```css
    // .hover\:foo:hover {}
    //       ^
    // ```
    //
    if (currentChar === BACKSLASH) {
      if (buffer === '') bufferStart = i
      buffer += input.slice(i, i + 2)
      i += 1
    }

    // Start of a comment.
    //
    // E.g.:
    //
    // ```css
    // /* Example */
    // ^^^^^^^^^^^^^
    // .foo {
    //  color: red; /* Example */
    //              ^^^^^^^^^^^^^
    // }
    // .bar {
    //  color: /* Example */ red;
    //         ^^^^^^^^^^^^^
    // }
    // ```
    else if (currentChar === SLASH && input.charCodeAt(i + 1) === ASTERISK) {
      let start = i

      for (let j = i + 2; j < input.length; j++) {
        peekChar = input.charCodeAt(j)

        // Current character is a `\` therefore the next character is escaped.
        if (peekChar === BACKSLASH) {
          j += 1
        }

        // End of the comment
        else if (peekChar === ASTERISK && input.charCodeAt(j + 1) === SLASH) {
          i = j + 1