substituteAtImports() — tailwindcss Function Reference

Architecture documentation for the substituteAtImports() function in at-import.ts from the tailwindcss codebase.

Function typescript OxideCore PreProcessors calls 5 called by 1

Entity Profile

OxideCore→ PreProcessors→ substituteAtImports() — tailwindcss Function Reference

Dependency Diagram

graph TD
  65cd5723_5f2b_da42_e83b_2add05ebc004["substituteAtImports()"]
  95cb326e_6b59_0903_0c96_d221fca5c2b1["parseCss()"]
  95cb326e_6b59_0903_0c96_d221fca5c2b1 -->|calls| 65cd5723_5f2b_da42_e83b_2add05ebc004
  a32bba76_f60d_883f_1ff1_276a0bb9db9f["walk()"]
  65cd5723_5f2b_da42_e83b_2add05ebc004 -->|calls| a32bba76_f60d_883f_1ff1_276a0bb9db9f
  ddd2db68_c731_a9de_a974_10945491851d["parseImportParams()"]
  65cd5723_5f2b_da42_e83b_2add05ebc004 -->|calls| ddd2db68_c731_a9de_a974_10945491851d
  a36324cc_cbd0_023c_1dc6_8ce6c9c41dda["context()"]
  65cd5723_5f2b_da42_e83b_2add05ebc004 -->|calls| a36324cc_cbd0_023c_1dc6_8ce6c9c41dda
  510b91a2_860c_62c6_54c4_43c0ad2f601c["buildImportNodes()"]
  65cd5723_5f2b_da42_e83b_2add05ebc004 -->|calls| 510b91a2_860c_62c6_54c4_43c0ad2f601c
  253418a1_4f08_cf0e_5b8e_c6392b9959eb["parse()"]
  65cd5723_5f2b_da42_e83b_2add05ebc004 -->|calls| 253418a1_4f08_cf0e_5b8e_c6392b9959eb
  style 65cd5723_5f2b_da42_e83b_2add05ebc004 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/tailwindcss/src/at-import.ts lines 16–81

export async function substituteAtImports(
  ast: AstNode[],
  base: string,
  loadStylesheet: LoadStylesheet,
  recurseCount = 0,
  track = false,
) {
  let features = Features.None
  let promises: Promise<void>[] = []

  walk(ast, (node) => {
    if (node.kind === 'at-rule' && (node.name === '@import' || node.name === '@reference')) {
      let parsed = parseImportParams(ValueParser.parse(node.params))
      if (parsed === null) return
      if (node.name === '@reference') {
        parsed.media = 'reference'
      }

      features |= Features.AtImport

      let { uri, layer, media, supports } = parsed

      // Skip importing data or remote URIs
      if (uri.startsWith('data:')) return
      if (uri.startsWith('http://') || uri.startsWith('https://')) return

      let contextNode = context({}, [])

      promises.push(
        (async () => {
          // Since we do not have fully resolved paths in core, we can't
          // reliably detect circular imports. Instead, we try to limit the
          // recursion depth to a number that is too large to be reached in
          // practice.
          if (recurseCount > 100) {
            throw new Error(
              `Exceeded maximum recursion depth while resolving \`${uri}\` in \`${base}\`)`,
            )
          }

          let loaded = await loadStylesheet(uri, base)
          let ast = CSS.parse(loaded.content, { from: track ? loaded.path : undefined })
          await substituteAtImports(ast, loaded.base, loadStylesheet, recurseCount + 1, track)

          contextNode.nodes = buildImportNodes(
            node,
            [context({ base: loaded.base }, ast)],
            layer,
            media,
            supports,
          )
        })(),
      )

      // The resolved Stylesheets already have their transitive @imports
      // resolved, so we can skip walking them.
      return WalkAction.ReplaceSkip(contextNode)
    }
  })

  if (promises.length > 0) {
    await Promise.all(promises)
  }

  return features
}