text: // @flow
  
  /**
   * This file handles all logic for converting string-based configuration references into loaded objects.
   */
  
  import buildDebug from "debug";
  import resolve from "resolve";
  import path from "path";
  
  const debug = buildDebug("babel:config:loading:files:plugins");
  
  const EXACT_RE = /^module:/;
  const BABEL_PLUGIN_PREFIX_RE = /^(?!@|module:|[^/]+\/|babel-plugin-)/;
  const BABEL_PRESET_PREFIX_RE = /^(?!@|module:|[^/]+\/|babel-preset-)/;
  const BABEL_PLUGIN_ORG_RE = /^(@babel\/)(?!plugin-|[^/]+\/)/;
  const BABEL_PRESET_ORG_RE = /^(@babel\/)(?!preset-|[^/]+\/)/;
  const OTHER_PLUGIN_ORG_RE = /^(@(?!babel\/)[^/]+\/)(?![^/]*babel-plugin(?:-|\/|$)|[^/]+\/)/;
  const OTHER_PRESET_ORG_RE = /^(@(?!babel\/)[^/]+\/)(?![^/]*babel-preset(?:-|\/|$)|[^/]+\/)/;
  const OTHER_ORG_DEFAULT_RE = /^(@(?!babel$)[^/]+)$/;
  
  export function resolvePlugin(name: string, dirname: string): string | null {
    return resolveStandardizedName("plugin", name, dirname);
  }
  
  export function resolvePreset(name: string, dirname: string): string | null {
    return resolveStandardizedName("preset", name, dirname);
  }
  
  export function loadPlugin(
    name: string,
    dirname: string,
  ): { filepath: string, value: mixed } {
    const filepath = resolvePlugin(name, dirname);
    if (!filepath) {
      throw new Error(`Plugin ${name} not found relative to ${dirname}`);
    }
  
    const value = requireModule("plugin", filepath);
    debug("Loaded plugin %o from %o.", name, dirname);
  
    return { filepath, value };
  }
  
  export function loadPreset(
    name: string,
    dirname: string,
  ): { filepath: string, value: mixed } {
    const filepath = resolvePreset(name, dirname);
    if (!filepath) {
      throw new Error(`Preset ${name} not found relative to ${dirname}`);
    }
  
    const value = requireModule("preset", filepath);
  
    debug("Loaded preset %o from %o.", name, dirname);
  
    return { filepath, value };
  }
  
  function standardizeName(type: "plugin" | "preset", name: string) {
    // Let absolute and relative paths through.
    if (path.isAbsolute(name)) return name;
  
    const isPreset = type === "preset";
  
    return (
      name
        // foo -> babel-preset-foo
        .replace(
          isPreset ? BABEL_PRESET_PREFIX_RE : BABEL_PLUGIN_PREFIX_RE,
          `babel-${type}-`,
        )
        // @babel/es2015 -> @babel/preset-es2015
        .replace(
          isPreset ? BABEL_PRESET_ORG_RE : BABEL_PLUGIN_ORG_RE,
          `$1${type}-`,
        )
        // @foo/mypreset -> @foo/babel-preset-mypreset
        .replace(
          isPreset ? OTHER_PRESET_ORG_RE : OTHER_PLUGIN_ORG_RE,
          `$1babel-${type}-`,
        )
        // @foo -> @foo/babel-preset
        .replace(OTHER_ORG_DEFAULT_RE, `$1/babel-${type}`)
        // module:mypreset -> mypreset
        .replace(EXACT_RE, "")
    );
  }
  
  function resolveStandardizedName(
    type: "plugin" | "preset",
    name: string,
    dirname: string = process.cwd(),
  ) {
    const standardizedName = standardizeName(type, name);
  
    try {
      return resolve.sync(standardizedName, { basedir: dirname });
    } catch (e) {
      if (e.code !== "MODULE_NOT_FOUND") throw e;
  
      if (standardizedName !== name) {
        let resolvedOriginal = false;
        try {
          resolve.sync(name, { basedir: dirname });
          resolvedOriginal = true;
        } catch (e2) {}
  
        if (resolvedOriginal) {
          e.message += `\n- If you want to resolve "${name}", use "module:${name}"`;
        }
      }
  
      let resolvedBabel = false;
      try {
        resolve.sync(standardizeName(type, "@babel/" + name), {
          basedir: dirname,
        });
        resolvedBabel = true;
      } catch (e2) {}
  
      if (resolvedBabel) {
        e.message += `\n- Did you mean "@babel/${name}"?`;
      }
  
      let resolvedOppositeType = false;
      const oppositeType = type === "preset" ? "plugin" : "preset";
      try {
        resolve.sync(standardizeName(oppositeType, name), { basedir: dirname });
        resolvedOppositeType = true;
      } catch (e2) {}
  
      if (resolvedOppositeType) {
        e.message += `\n- Did you accidentally pass a ${oppositeType} as a ${type}?`;
      }
  
      throw e;
    }
  }
  
  const LOADING_MODULES = new Set();
  function requireModule(type: string, name: string): mixed {
    if (LOADING_MODULES.has(name)) {
      throw new Error(
        `Reentrant ${type} detected trying to load "${name}". This module is not ignored ` +
          "and is trying to load itself while compiling itself, leading to a dependency cycle. " +
          'We recommend adding it to your "ignore" list in your babelrc, or to a .babelignore.',
      );
    }
  
    try {
      LOADING_MODULES.add(name);
      // $FlowIssue
      return require(name);
    } finally {
      LOADING_MODULES.delete(name);
    }
  }
  