parseCss() — tailwindcss Function Reference

Source Code

packages/tailwindcss/src/index.ts lines 141–707

async function parseCss(
  ast: AstNode[],
  {
    base = '',
    from,
    loadModule = throwOnLoadModule,
    loadStylesheet = throwOnLoadStylesheet,
  }: CompileOptions = {},
) {
  let features = Features.None
  ast = [contextNode({ base }, ast)] as AstNode[]

  features |= await substituteAtImports(ast, base, loadStylesheet, 0, from !== undefined)

  let important = null as boolean | null
  let theme = new Theme()
  let customVariants = new Map<string, (designSystem: DesignSystem) => void>()
  let customVariantDependencies = new Map<string, Set<string>>()
  let customUtilities: ((designSystem: DesignSystem) => void)[] = []
  let firstThemeRule = null as StyleRule | null
  let utilitiesNode = null as AtRule | null
  let variantNodes: AtRule[] = []
  let sources: { base: string; pattern: string; negated: boolean }[] = []
  let inlineCandidates: string[] = []
  let ignoredCandidates: string[] = []
  let root = null as Root

  // Handle at-rules
  walk(ast, (node, _ctx) => {
    if (node.kind !== 'at-rule') return
    let ctx = cssContext(_ctx)

    // Find `@tailwind utilities` so that we can later replace it with the
    // actual generated utility class CSS.
    if (
      node.name === '@tailwind' &&
      (node.params === 'utilities' || node.params.startsWith('utilities'))
    ) {
      // Any additional `@tailwind utilities` nodes can be removed
      if (utilitiesNode !== null) {
        return WalkAction.Replace([])
      }

      // When inside `@reference` we should treat `@tailwind utilities` as if
      // it wasn't there in the first place. This should also let `build()`
      // return the cached static AST.
      if (ctx.context.reference) {
        return WalkAction.Replace([])
      }

      let params = segment(node.params, ' ')
      for (let param of params) {
        if (param.startsWith('source(')) {
          let path = param.slice(7, -1)

          // Keyword: `source(none)`
          if (path === 'none') {
            root = path
            continue
          }

          // Explicit path: `source('…')`
          if (
            (path[0] === '"' && path[path.length - 1] !== '"') ||
            (path[0] === "'" && path[path.length - 1] !== "'") ||
            (path[0] !== "'" && path[0] !== '"')
          ) {
            throw new Error('`source(…)` paths must be quoted.')
          }

          root = {
            base: (ctx.context.sourceBase as string) ?? (ctx.context.base as string),
            pattern: path.slice(1, -1),
          }
        }
      }

      utilitiesNode = node
      features |= Features.Utilities
    }