Method parameters matching enum value in TypeScript

Question

I want to create a type match when calling a method with enum values.

Imagine the next example:

enum Vehicle {
  Car,
  Bus,
  Plane
};

type CarParams = { carId: string };
type BusParams = { busId: string };
type PlaneParams = { planeId: string };

const TypeMap = {
  [Vehicle.Car]: CarParams,
  [Vehicle.Bus]: BusParams,
  [Vehicle.Plane]: PlaneParams,
};

function showDriver(vehicle: Vehicle, params: TypeMap[valueof vehicle]): void {
  // ...
}

I can't really do this: TypeMap[valueof vehicle] But I want to help whoever uses my method to understand the parameters they need to send, so that calls look like this:

showDriver(Vehicle.Bus, { busI...

This would automatically autocomplete to busId and expect a string.

How do I do that?

Anarno · Accepted Answer · 2022-03-10 07:15:11Z

1

This is how you can achive:

enum Vehicle {
    Car,
    Bus,
    Plane,
}

interface CarParams {
    carId: string;
}

interface BusParams {
    busId: string;
}

interface PlaneParams {
    planeId: string;
}

type Params = {
    [Vehicle.Bus]: BusParams;
    [Vehicle.Car]: CarParams;
    [Vehicle.Plane]: PlaneParams;
};

function showDriver<T extends Vehicle>(vehicle: T, params: Params[T] ): void {
  // ...
}

answered Mar 10, 2022 at 7:15

Anarno

1,64012 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Method parameters matching enum value in TypeScript

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related