Error Handling

Use app.useErrors(...) near the top of your app so later middleware and routes share one error policy.

import { Config, RequestId, Results, Sloppy } from "sloppy";

const app = Sloppy.create();

app.useErrors({
  includeDetails: Config.boolean("Errors:IncludeDetails", false),
});
app.use(RequestId.defaults());

By default, Sloppy returns safe problem responses. Internal exception messages and stack traces are hidden. Turn details on only for local development:

app.useErrors({ detail: "development" });

Typed mappings are useful for domain errors:

class NotFoundError extends Error {}

app.mapError(NotFoundError, (err, ctx) =>
  Results.problem({
    status: 404,
    title: "Not found",
    detail: err.message,
    requestId: ctx.requestId,
  }, { status: 404 })
);

Request validation failures from ctx.body.validate(...) already produce 400 application/problem+json. Auth failures already produce 401 or 403. Provider-shaped errors are intentionally redacted even when detail output is enabled.

For tests, Testing.createHost(app) also applies the policy to missing routes, unsupported media types, and oversized request bodies.

Error Handling ​

Error Handling