Filtering for 2xx Status Only | Effect Http Client

If you want non-2xx status codes to be treated as errors, use filterStatusOk on the client:

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import {
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  FetchHttpClient,
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  HttpClient,
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  HttpClientRequest,
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} from "effect/unstable/http";
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import { Effect } from "effect";
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function fetchUser(userId: number) {
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  return Effect.gen(function* () {
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    const client = (yield* HttpClient.HttpClient).pipe(
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      // All requests through this client will fail on non-2xx
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      HttpClient.filterStatusOk,
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    );
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    const request = HttpClientRequest.get(
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      `https://dummyjson.com/users/${userId}`,
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    );
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    const response = yield* client.execute(request);
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    const user = yield* response.json;
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    return user;
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  }).pipe(Effect.provide(FetchHttpClient.layer));
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}
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// Test with a valid user
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Effect.runPromise(fetchUser(1)).then(
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  (user) => console.log("Found:", user.firstName),
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  (error) => console.error("Error:", error.message),
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);
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// Test with an invalid user
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Effect.runPromise(fetchUser(9999)).then(
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  (user) => console.log("Found:", user.firstName),
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  (error) => console.error("Error:", error.message),
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);

Output:

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Error: StatusCode: non 2xx status code (404 GET https://dummyjson.com/users/9999)
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Found: Emily

When filterStatusOk rejects a response, it produces an HttpClientError with reason set to a StatusCodeError. The error includes both the original request and the response, so you have full context for debugging or recovery.

You can also use filterStatus for more control. It takes a predicate that receives the status code:

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// Only accept 200 and 201
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HttpClient.filterStatus((status) => status === 200 || status === 201);

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