/dx-audit

Let Inference Do the Work

The caller should rarely write a type annotation. If your API requires manually specifying generic parameters or annotating results, the signatures are under-inferring. Design generics so the return type flows from the arguments.

Incorrect (caller must annotate because the result is not inferred):

function get<T>(key: string): T {}
const port = get<number>("port"); // forced annotation, and it is a lie:
                                  // the cast is unchecked

Correct (return type flows from a typed schema argument):

function get<T>(key: string, schema: Schema<T>): T {}
const port = get("port", z.number()); // T inferred as number, validated