| # enhanced-resolve |
|
|
| [![npm][npm]][npm-url] |
| [![Build Status][build-status]][build-status-url] |
| [![codecov][codecov-badge]][codecov-url] |
| [![Install Size][size]][size-url] |
| [![GitHub Discussions][discussion]][discussion-url] |
|
|
| Offers an async require.resolve function. It's highly configurable. |
|
|
| ## Features |
|
|
| - plugin system |
| - provide a custom filesystem |
| - sync and async node.js filesystems included |
|
|
| ## Getting Started |
|
|
| ### Install |
|
|
| ```sh |
| # npm |
| npm install enhanced-resolve |
| # or Yarn |
| yarn add enhanced-resolve |
| ``` |
|
|
| ### Resolve |
|
|
| There is a Node.js API which allows to resolve requests according to the Node.js resolving rules. |
| Sync and async APIs are offered. A `create` method allows to create a custom resolve function. |
|
|
| ```js |
| const resolve = require("enhanced-resolve"); |
| |
| resolve("/some/path/to/folder", "module/dir", (err, result) => { |
| result; // === "/some/path/node_modules/module/dir/index.js" |
| }); |
| |
| resolve.sync("/some/path/to/folder", "../../dir"); |
| // === "/some/path/dir/index.js" |
| |
| const myResolve = resolve.create({ |
| // or resolve.create.sync |
| extensions: [".ts", ".js"], |
| // see more options below |
| }); |
| |
| myResolve("/some/path/to/folder", "ts-module", (err, result) => { |
| result; // === "/some/node_modules/ts-module/index.ts" |
| }); |
| ``` |
|
|
| ### Creating a Resolver |
|
|
| The easiest way to create a resolver is to use the `createResolver` function on `ResolveFactory`, along with one of the supplied File System implementations. |
|
|
| ```js |
| const fs = require("fs"); |
| const { CachedInputFileSystem, ResolverFactory } = require("enhanced-resolve"); |
| |
| // create a resolver |
| const myResolver = ResolverFactory.createResolver({ |
| // Typical usage will consume the `fs` + `CachedInputFileSystem`, which wraps Node.js `fs` to add caching. |
| fileSystem: new CachedInputFileSystem(fs, 4000), |
| extensions: [".js", ".json"], |
| /* any other resolver options here. Options/defaults can be seen below */ |
| }); |
| |
| // resolve a file with the new resolver |
| const context = {}; |
| const lookupStartPath = "/Users/webpack/some/root/dir"; |
| const request = "./path/to-look-up.js"; |
| const resolveContext = {}; |
| myResolver.resolve( |
| context, |
| lookupStartPath, |
| request, |
| resolveContext, |
| (err /* Error */, filepath /* string */) => { |
| // Do something with the path |
| }, |
| ); |
| ``` |
|
|
| #### Resolver Options |
|
|
| | Field | Default | Description | |
| | ------------------- | --------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | |
| | alias | [] | A list of module alias configurations or an object which maps key to value | |
| | aliasFields | [] | A list of alias fields in description files | |
| | extensionAlias | {} | An object which maps extension to extension aliases | |
| | cachePredicate | function() { return true }; | A function which decides whether a request should be cached or not. An object is passed to the function with `path` and `request` properties. | |
| | cacheWithContext | true | If unsafe cache is enabled, includes `request.context` in the cache key | |
| | conditionNames | [] | A list of exports field condition names | |
| | descriptionFiles | ["package.json"] | A list of description files to read from | |
| | enforceExtension | false | Enforce that a extension from extensions must be used | |
| | exportsFields | ["exports"] | A list of exports fields in description files | |
| | extensions | [".js", ".json", ".node"] | A list of extensions which should be tried for files | |
| | fallback | [] | Same as `alias`, but only used if default resolving fails | |
| | fileSystem | | The file system which should be used | |
| | fullySpecified | false | Request passed to resolve is already fully specified and extensions or main files are not resolved for it (they are still resolved for internal requests) | |
| | mainFields | ["main"] | A list of main fields in description files | |
| | mainFiles | ["index"] | A list of main files in directories | |
| | modules | ["node_modules"] | A list of directories to resolve modules from, can be absolute path or folder name | |
| | plugins | [] | A list of additional resolve plugins which should be applied | |
| | resolver | undefined | A prepared Resolver to which the plugins are attached | |
| | resolveToContext | false | Resolve to a context instead of a file | |
| | preferRelative | false | Prefer to resolve module requests as relative request and fallback to resolving as module | |
| | preferAbsolute | false | Prefer to resolve server-relative urls as absolute paths before falling back to resolve in roots | |
| | restrictions | [] | A list of resolve restrictions | |
| | roots | [] | A list of root paths | |
| | symlinks | true | Whether to resolve symlinks to their symlinked location | |
| | tsconfig | false | TypeScript config for paths mapping. Can be `false` (disabled), `true` (use default `tsconfig.json`), a string path to `tsconfig.json`, or an object with `configFile`, `references`, and `baseUrl` options. Supports JSONC format (comments and trailing commas) like TypeScript compiler. | |
| | tsconfig.configFile | tsconfig.json | Path to the tsconfig.json file | |
| | tsconfig.references | [] | Project references. `'auto'` to load from tsconfig, or an array of paths to referenced projects | |
| | tsconfig.baseUrl | undefined | Override baseUrl from tsconfig.json. If provided, this value will be used instead of the baseUrl in the tsconfig file | |
| | unsafeCache | false | Use this cache object to unsafely cache the successful requests | |
| |
| ## Plugins |
| |
| Similar to `webpack`, the core of `enhanced-resolve` functionality is implemented as individual plugins that are executed using [`tapable`](https://github.com/webpack/tapable). |
| These plugins can extend the functionality of the library, adding other ways for files/contexts to be resolved. |
| |
| A plugin should be a `class` (or its ES5 equivalent) with an `apply` method. The `apply` method will receive a `resolver` instance, that can be used to hook in to the event system. |
| |
| ### Plugin Boilerplate |
| |
| ```js |
| class MyResolverPlugin { |
| constructor(source, target) { |
| this.source = source; |
| this.target = target; |
| } |
| |
| apply(resolver) { |
| const target = resolver.ensureHook(this.target); |
| resolver |
| .getHook(this.source) |
| .tapAsync("MyResolverPlugin", (request, resolveContext, callback) => { |
| // Any logic you need to create a new `request` can go here |
| resolver.doResolve(target, request, null, resolveContext, callback); |
| }); |
| } |
| } |
| ``` |
| |
| Plugins are executed in a pipeline, and register which event they should be executed before/after. In the example above, `source` is the name of the event that starts the pipeline, and `target` is what event this plugin should fire, which is what continues the execution of the pipeline. For an example of how these different plugin events create a chain, see `lib/ResolverFactory.js`, in the `//// pipeline ////` section. |
| |
| ## Escaping |
| |
| It's allowed to escape `#` as `\0#` to avoid parsing it as fragment. |
| |
| enhanced-resolve will try to resolve requests containing `#` as path and as fragment, so it will automatically figure out if `./some#thing` means `.../some.js#thing` or `.../some#thing.js`. When a `#` is resolved as path it will be escaped in the result. Here: `.../some\0#thing.js`. |
| |
| ## Tests |
| |
| ```sh |
| npm run test |
| ``` |
| |
| ## Passing options from webpack |
| |
| If you are using `webpack`, and you want to pass custom options to `enhanced-resolve`, the options are passed from the `resolve` key of your webpack configuration e.g.: |
| |
| ``` |
| resolve: { |
| extensions: ['.js', '.jsx'], |
| modules: [path.resolve(__dirname, 'src'), 'node_modules'], |
| plugins: [new DirectoryNamedWebpackPlugin()] |
| ... |
| }, |
| ``` |
| |
| ## License |
| |
| Copyright (c) 2012-2019 JS Foundation and other contributors |
| |
| MIT (http://www.opensource.org/licenses/mit-license.php) |
| |
| [npm]: https://img.shields.io/npm/v/enhanced-resolve.svg |
| [npm-url]: https://www.npmjs.com/package/enhanced-resolve |
| [build-status]: https://github.com/webpack/enhanced-resolve/actions/workflows/test.yml/badge.svg |
| [build-status-url]: https://github.com/webpack/enhanced-resolve/actions |
| [codecov-badge]: https://codecov.io/gh/webpack/enhanced-resolve/branch/main/graph/badge.svg?token=6B6NxtsZc3 |
| [codecov-url]: https://codecov.io/gh/webpack/enhanced-resolve |
| [size]: https://packagephobia.com/badge?p=enhanced-resolve |
| [size-url]: https://packagephobia.com/result?p=enhanced-resolve |
| [discussion]: https://img.shields.io/github/discussions/webpack/webpack |
| [discussion-url]: https://github.com/webpack/webpack/discussions |
| |
