Workers Polyfills

This directory contains polyfills for modules unsupported by workerd, but required by Vitest. Files in this directory map directly to imports inside workerd (see ../../pool/module-fallback.ts). For example, lib/cloudflare/test.ts becomes cloudflare:test.

Files ending in .ts will be bundled into ES modules, meaning they can only be imported. Files ending in .cts will be bundled into CommonJS modules, meaning they can be imported and require()ed from other CommonJS modules. Note our implementation of the module fallback service applies Node's ESM-CJS named-exports interop meaning named-exports in .cts files can still be imported as such in ES modules.