Question: Object as value in custom constraint

[matthyk]

Since version 4.0.0, it is possible to write your own constraint strategies. In the index.d.ts, however, it is specified that the values for the constraints must be strings. So my question is whether it is safe to also take object as values, as in the example below.

Current typing in index.d.ts:

interface ConstraintStrategy<V extends HTTPVersion> {
    name: string,
    mustMatchWhenDerived?: boolean,
    storage() : {
      get(version: String) : Handler<V> | null,
      set(version: String, store: Handler<V>) : void,
      del(version: String) : void,
      empty() : void
    },
    validate(value: unknown): void,
    deriveConstraint<Context>(req: Req<V>, ctx?: Context) : String,
  }

Example with an object as key instead of a string:

interface MyObject {
    myProperty: string;
    mySecondProperty: string;
    myNumberProperty: number;
}

interface ConstraintStrategy<V extends HTTPVersion> {
    name: string,
    mustMatchWhenDerived?: boolean,
    storage() : {
      get(version: MyObject) : Handler<V> | null,
      set(version: MyObject, store: Handler<V>) : void,
      del(version: MyObject) : void,
      empty() : void
    },
    validate(value: unknown): void,
    deriveConstraint<Context>(req: Req<V>, ctx?: Context) : MyObject,
  }

Could be typed in the index.d.ts like this:

interface ConstraintStrategy<V extends HTTPVersion, T = string> {
    name: string,
    mustMatchWhenDerived?: boolean,
    storage() : {
      get(version: T) : Handler<V> | null,
      set(version: T, store: Handler<V>) : void,
      del(version: T) : void,
      empty() : void
    },
    validate(value: unknown): void,
    deriveConstraint<Context>(req: Req<V>, ctx?: Context) : T,
  }

[mcollina]

I would say that the best way is to send a PR and figure things out :).

[matthyk]

Created PR #180