node:path

Path manipulation is portable, but path.resolve() and related operations need a current working directory.

Jco obtains that value through wasi:cli/environment. The selected WIT world can import one P2 or P3 version, which determines the adapter Jco uses:

world app {
  import wasi:cli/environment@0.2.6;
  // component imports and exports...
}

For P3, declare wasi:cli/environment@0.3.0 and build with jco componentize --bundle --backend qjs. P3 componentization currently requires componentize-qjs.

Both package paths export the same createPath factory and Node 24 types. The P3 adapter imports getInitialCwd as initialCwd, matching the existing factory’s provider contract, and normalizes an absent cwd to undefined; the path algorithms remain shared. When using the factory directly, pass { initialCwd: () => getInitialCwd() ?? undefined, getEnvironment } from the P3 environment interface. This also accepts QuickJS’s null representation of an absent WIT option.

When the component’s WIT exports use async func, implement those JavaScript exports with async functions for QuickJS. The node:path methods themselves remain synchronous.

Importing multiple supported environment versions, including a mix of P2 and P3, is ambiguous and rejected. If no supported environment import is present, Jco still adds the existing P2 wasi:cli/environment@0.2.12 requirement. P3 users must declare the P3 environment import explicitly for this adapter.

This P3 support covers node:path; other built-ins are being reviewed separately. A component that only uses capability-free built-ins such as assert, Buffer, or querystring does not need the environment import.