resolvePackageEntry() — vite Function Reference

Source Code

packages/vite/src/node/plugins/resolve.ts lines 903–991

export function resolvePackageEntry(
  id: string,
  { dir, data, setResolvedCache, getResolvedCache }: PackageData,
  options: InternalResolveOptions,
  externalize?: boolean,
): string | undefined {
  const { file: idWithoutPostfix, postfix } = splitFileAndPostfix(id)

  const cached = getResolvedCache('.', options)
  if (cached) {
    return cached + postfix
  }

  try {
    let entryPoint: string | undefined

    // resolve exports field with highest priority
    // using https://github.com/lukeed/resolve.exports
    if (data.exports) {
      entryPoint = resolveExportsOrImports(
        data,
        '.',
        options,
        'exports',
        externalize,
      )
    }

    // fallback to mainFields if still not resolved
    if (!entryPoint) {
      for (const field of options.mainFields) {
        if (field === 'browser') {
          entryPoint = tryResolveBrowserEntry(dir, data, options)
          if (entryPoint) {
            break
          }
        } else if (typeof data[field] === 'string') {
          entryPoint = data[field]
          break
        }
      }
    }
    entryPoint ||= data.main

    // try default entry when entry is not define
    // https://nodejs.org/api/modules.html#all-together
    const entryPoints = entryPoint
      ? [entryPoint]
      : ['index.js', 'index.json', 'index.node']

    for (let entry of entryPoints) {
      // make sure we don't get scripts when looking for sass
      let skipPackageJson = false
      if (
        options.mainFields[0] === 'sass' &&
        !options.extensions.includes(path.extname(entry))
      ) {
        entry = ''
        skipPackageJson = true
      } else {
        // resolve object browser field in package.json
        const { browser: browserField } = data
        if (options.mainFields.includes('browser') && isObject(browserField)) {
          entry = mapWithBrowserField(entry, browserField) || entry
        }
      }

      const entryPointPath = path.join(dir, entry)
      const resolvedEntryPoint = tryFsResolve(
        entryPointPath,
        options,
        true,
        skipPackageJson,
      )
      if (resolvedEntryPoint) {
        debug?.(
          `[package entry] ${colors.cyan(idWithoutPostfix)} -> ${colors.dim(
            resolvedEntryPoint,
          )}${postfix !== '' ? ` (postfix: ${postfix})` : ''}`,
        )
        setResolvedCache('.', resolvedEntryPoint, options)