oxc-project
Oxc Resolver
Rust port of enhanced-resolve.
- Released on crates.io and npm.
- Implements the ESM and CommonJS module resolution algorithm specification.
- Built-in tsconfig-paths-webpack-plugin
- support extending tsconfig defined in
tsconfig.extends - support paths alias defined in
tsconfig.compilerOptions.paths - support project references defined
tsconfig.references - support template variable ${configDir} for substitution of config files directory path
- support extending tsconfig defined in
- Supports in-memory file system via the
FileSystemtrait. - Contains
tracinginstrumentation.
Usage
npm package
See index.d.ts for resolveSync and ResolverFactory API.
Quick example:
import assert from 'assert';
import path from 'path';
import resolve, { ResolverFactory } from './index.js';
// `resolve`
assert(resolve.sync(process.cwd(), './index.js').path, path.join(cwd, 'index.js'));
// `ResolverFactory`
const resolver = new ResolverFactory();
assert(resolver.sync(process.cwd(), './index.js').path, path.join(cwd, 'index.js'));
Supports WASM
See https://stackblitz.com/edit/oxc-resolver for usage example.
Rust
See docs.rs/oxc_resolver.
Terminology
directory
An absolute path to a directory where the specifier is resolved against.
For CommonJS modules, it is the __dirname variable that contains the absolute path to the folder containing current module.
For ECMAScript modules, it is the value of import.meta.url.
Behavior is undefined when given a path to a file.
specifier
The string passed to require or import, i.e. require("specifier") or import "specifier"
Errors and Trouble Shooting
Error: Package subpath '.' is not defined by "exports" in- occurs when resolving withoutconditionNames.
Configuration
The following usages apply to both Rust and Node.js; the code snippets are written in JavaScript.
To handle the exports field in package.json, ESM and CJS need to be differentiated.
ESM
defaultConditions is the conditional environment name array, ["node", "import"].
This means when the caller is an ESM import (import "module"), resolve options should be
{
"conditionNames": ["node", "import"]
}
CJS
LOAD_PACKAGE_EXPORTS(X, DIR)
- let MATCH = PACKAGE_EXPORTS_RESOLVE(pathToFileURL(DIR/NAME), "." + SUBPATH,
package.json"exports", ["node", "require"]) defined in the ESM resolver.
This means when the caller is a CJS require (require("module")), resolve options should be
{
"conditionNames": ["node", "require"]
}
Cache
To support both CJS and ESM with the same cache:
const esmResolver = new ResolverFactory({
conditionNames: ['node', 'import'],
});
const cjsResolver = esmResolver.cloneWithOptions({
conditionNames: ['node', 'require'],
});
Browser Field
From this non-standard spec:
The
browserfield is provided to JavaScript bundlers or component tools when packaging modules for client side use.
The option is
{
"aliasFields": ["browser"]
}
Main Field
{
"mainFields": ["module", "main"]
}
Quoting esbuild's documentation:
main- This is the standard field for all packages that are meant to be used with node. The name main is hard-coded in to node's module resolution logic itself. Because it's intended for use with node, it's reasonable to expect that the file path in this field is a CommonJS-style module.module- This field came from a proposal for how to integrate ECMAScript modules into node. Because of this, it's reasonable to expect that the file path in this field is an ECMAScript-style module. This proposal wasn't adopted by node (node uses "type": "module" instead) but it was adopted by major bundlers because ECMAScript-style modules lead to better tree shaking, or dead code removal.browser- This field came from a proposal that allows bundlers to replace node-specific files or modules with their browser-friendly versions. It lets you specify an alternate browser-specific entry point. Note that it is possible for a package to use both the browser and module field together (see the note below).
Options
The following options are aligned with enhanced-resolve, and is implemented for Rust crate usage.
See index.d.ts for Node.js usage.
| 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 |
| conditionNames | [] | A list of exports field condition names |
| 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 |
| 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 |
Unimplemented Options
| Field | Default | Description |
|---|---|---|
| descriptionFiles | ["package.json"] | A list of description files to read from |
| 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 |
| plugins | [] | A list of additional resolve plugins which should be applied |
| resolver | undefined | A prepared Resolver to which the plugins are attached |
| unsafeCache | false | Use this cache object to unsafely cache the successful requests |
Debugging
The following environment variable emits tracing information for the oxc_resolver::resolve function.
e.g.
2024-06-11T07:12:20.003537Z DEBUG oxc_resolver: options: ResolveOptions { ... }, path: "...", specifier: "...", ret: "..."
at /path/to/oxc_resolver-1.8.1/src/lib.rs:212
in oxc_resolver::resolve with path: "...", specifier: "..."
The input values are options, path and specifier, the returned value is ret.
NAPI
OXC_LOG=DEBUG your_program
Rolldown
RD_LOG='oxc_resolver' rolldown build
Test
Tests are ported from
- enhanced-resolve
- tsconfig-path and parcel-resolver for tsconfig-paths
Test cases are located in ./src/tests, fixtures are located in ./tests
- [x] alias.test.js
- [x] browserField.test.js
- [x] dependencies.test.js
- [x] exportsField.test.js
- [x] extension-alias.test.js
- [x] extensions.test.js
- [x] fallback.test.js
- [x] fullSpecified.test.js
- [x] identifier.test.js (see unit test in
crates/oxc_resolver/src/request.rs) - [x] importsField.test.js
- [x] incorrect-description-file.test.js (need to add ctx.fileDependencies)
- [x] missing.test.js
- [x] path.test.js (see unit test in
crates/oxc_resolver/src/path.rs) - [ ] plugins.test.js
- [ ] pnp.test.js
- [x] resolve.test.js
- [x] restrictions.test.js (partially done, regex is not supported yet)
- [x] roots.test.js
- [x] scoped-packages.test.js
- [x] simple.test.js
- [x] symlink.test.js
Irrelevant tests
- CachedInputFileSystem.test.js
- SyncAsyncFileSystemDecorator.test.js
- forEachBail.test.js
- getPaths.test.js
- pr-53.test.js
- unsafe-cache.test.js
- yield.test.js
Sponsored By
📖 License
oxc_resolver is free and open-source software licensed under the MIT License.
Oxc partially copies code from the following projects.
| Project | License |
|---|---|
| webpack/enhanced-resolve | MIT |
| dividab/tsconfig-paths | MIT |
| parcel-bundler/parcel | MIT |
| tmccombs/json-comments-rs | Apache 2.0 |