/**
 * ## Barrel Optimizations
 *
 * This loader is used to optimize the imports of "barrel" files that have many
 * re-exports. Currently, both Node.js and Webpack have to enter all of these
 * submodules even if we only need a few of them.
 *
 * For example, say a file `foo.js` with the following contents:
 *
 *   export { a } from './a'
 *   export { b } from './b'
 *   export { c } from './c'
 *   ...
 *
 * If the user imports `a` only, this loader will accept the `names` option to
 * be `['a']`. Then, it request the "__barrel_transform__" SWC transform to load
 * `foo.js` and receive the following output:
 *
 *   export const __next_private_export_map__ = '[["a","./a","a"],["b","./b","b"],["c","./c","c"],...]'
 *
 *   format: '["<imported identifier>", "<import path>", "<exported name>"]'
 *   e.g.: import { a as b } from './module-a' => '["b", "./module-a", "a"]'
 *
 * The export map, generated by SWC, is a JSON that represents the exports of
 * that module, their original file, and their original name (since you can do
 * `export { a as b }`).
 *
 * Then, this loader can safely remove all the exports that are not needed and
 * re-export the ones from `names`:
 *
 *   export { a } from './a'
 *
 * That's the basic situation and also the happy path.
 *
 *
 *
 * ## Wildcard Exports
 *
 * For wildcard exports (e.g. `export * from './a'`), it becomes a bit more complicated.
 * Say `foo.js` with the following contents:
 *
 *   export * from './a'
 *   export * from './b'
 *   export * from './c'
 *   ...
 *
 * If the user imports `bar` from it, SWC can never know which files are going to be
 * exporting `bar`. So, we have to keep all the wildcard exports and do the same
 * process recursively. This loader will return the following output:
 *
 *   export * from '__barrel_optimize__?names=bar&wildcard!=!./a'
 *   export * from '__barrel_optimize__?names=bar&wildcard!=!./b'
 *   export * from '__barrel_optimize__?names=bar&wildcard!=!./c'
 *   ...
 *
 * The "!=!" tells Webpack to use the same loader to process './a', './b', and './c'.
 * After the recursive process, the "inner loaders" will either return an empty string
 * or:
 *
 *   export * from './target'
 *
 * Where `target` is the file that exports `bar`.
 *
 *
 *
 * ## Non-Barrel Files
 *
 * If the file is not a barrel, we can't apply any optimizations. That's because
 * we can't easily remove things from the file. For example, say `foo.js` with:
 *
 *   const v = 1
 *   export function b () {
 *     return v
 *   }
 *
 * If the user imports `b` only, we can't remove the `const v = 1` even though
 * the file is side-effect free. In these caes, this loader will simply re-export
 * `foo.js`:
 *
 *   export * from './foo'
 *
 * Besides these cases, this loader also carefully handles the module cache so
 * SWC won't analyze the same file twice, and no instance of the same file will
 * be accidentally created as different instances.
 */
import type webpack from 'webpack';
declare const NextBarrelLoader: (this: webpack.LoaderContext<{
    names: string[];
    swcCacheDir: string;
}>) => Promise<void>;
export default NextBarrelLoader;