168 lines
9.8 KiB
Markdown
168 lines
9.8 KiB
Markdown
# enhanced-resolve
|
|
|
|
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 resolveContext = {};
|
|
const lookupStartPath = "/Users/webpack/some/root/dir";
|
|
const request = "./path/to-look-up.js";
|
|
myResolver.resolve({}, 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 |
|
|
| 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 | ["node"] | 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 |
|
|
| 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
|
|
|
|
```javascript
|
|
npm test
|
|
```
|
|
|
|
[](http://travis-ci.org/webpack/enhanced-resolve)
|
|
|
|
## 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)
|