effect-platform-abstraction

Use the FileSystem.FileSystem service from the effect package instead of fs or Bun.file. Access it with yield* FileSystem.FileSystem inside Effect.gen, then call readFileString or readFile, and provide NodeServices.layer or BunServices.layer at runtime.

Use the HttpClient service from effect/unstable/http instead of fetch or axios. It integrates with the Effect type system for typed errors, supports Schema-based response parsing, retries with Schedule, and works across platforms with layers like FetchHttpClient.layer or NodeHttpClient.layerUndici.

Yes, the same Effect code runs on both runtimes. Provide NodeServices.layer with NodeRuntime for Node.js or BunServices.layer with BunRuntime for Bun; both layers include FileSystem, Path, ChildProcessSpawner, Terminal, and Crypto services.

Use ChildProcess.make to build commands and ChildProcessSpawner from effect/unstable/process to execute them. The spawner supports string output, line collection, piping between commands, environment variables, and streaming stdout with exit code handling.

The error occurs when platform services are required but no layer is provided. Provide NodeServices.layer or BunServices.layer via Effect.provide before running; note that HTTP clients, sockets, and workers need separate service-specific layers.

Create a mock layer with Layer.succeed and FileSystem.makeNoop, overriding only the methods your code calls. Provide this test layer with Effect.provide to run your program without touching the real filesystem.