This is the simplest fallback strategy of the three. It relies only on stripping .js and /index.js (and corresponding .d.ts and /index.d.ts) suffixes when a non-exports-supporting resolver attempts to resolve a subpath:
import "extensionless/one";An exports-supporting resolver will look up "./one" in the package.json exports, which in turn points to "./one.js". A non-exports-supporting resolver will look for ./one (with no file extension) on the file system, and assuming it is not found, will try ./one.js, arriving at the same resolution through different means. (TypeScript’s non-exports-supporting moduleResolution modes will do the same, but trying .ts and .d.ts extensions instead of .js.)
import "extensionless/two";Likewise, a non-exports-supporting resolver will try ./two, ./two.js, and this time move onto ./two/index.js.
Pros:
- Well-supported
- Simple
- No configuration update needed when adding additional subpaths
Cons:
- Cannot accommodate a
distfolder - Cannot support mappings that do something besides extension/index removal