parcel-resolver

parcel-resolver implements the Node.js module resolution algorithm. It supports both CommonJS and ES module resolution, along with many additional features supported by various tools in the JavaScript ecosystem, such as TypeScript's tsconfig paths and extension rewriting, the "alias" and "browser" fields used by bundlers, absolute and tilde paths, and more. These can be individually turned on or off using feature flags.

For a full description of all supported resolution features, see Parcel's documentation.

Example

To create a resolver, first create a [Cache]. This stores information about the files in a [FileSystem], and can be reused between multiple resolvers. A fresh cache should generally be created once per build to ensure information is up to date.

Next, create a [Resolver] using one of the constructors. For example, Resolver::node creates a Node.js compatible CommonJS resolver, Resolver::node_esm creates an ESM resolver, and Resolver::parcel creates a Parcel-compatible resolver. From there you can customize individual features such as extensions or index files by setting properties on the resolver.

Finally, call resolver.resolve to resolve a specifier. This returns a result, along with [Invalidations] describing the files that should invalidate any resolution caches.

use parcel_resolver::{Cache, Resolver, SpecifierType, ResolutionAndQuery};
use std::path::Path;

let cache = Cache::default();
let resolver = Resolver::node_esm(Path::new("/path/to/project-root"), &cache);

let res = resolver.resolve(
  "lodash",
  Path::new("/path/to/project-root/index.js"),
  SpecifierType::Esm
);

if let Ok(ResolutionAndQuery { resolution, query }) = res.result {
  // Do something with the resolution!
}