TypeScript - Check if given 'any' parameter is custom type?

Question

I have a function template like this:

function (..., args: any) {...}

And I have a class called CreateLobbyParameter :

export class CreateLobbyParameter {
    userId: number;
    gameMode: GameMode;
}

If given any typed args parameter is not similar to CreateLobbyParameter (e.g. {userId: 0, gameMode: 0}, but not {userId:0}); I wanna handle that situation.

I've tried typeof(arg as CreateLobbyParameter), but it returns the string "object" for the parameter {userId: 0, gameMode: 0}, and not CreateLobbyParameter.

Also, arg instanceof CreateLobbyParameter returns false.

Not very clear what are you trying to do, are you trying to type a function that takes any as an argument? — asosnovsky
– asosnovsky, Commented Dec 27, 2017 at 16:03
You should probably define an interface for args instead of typing it as any. — JohnnyHK
– JohnnyHK, Commented Dec 27, 2017 at 16:05
Johnny, but it's properties are flexible, they change depending to its place. — Talha Talip Açıkgöz
– Talha Talip Açıkgöz, Commented Dec 27, 2017 at 16:12

Dan Schnau · Accepted Answer · 2017-12-27 16:20:40Z

2

Treat it like JavaScript.

var userId = arg.userId;
var gameMode = arg.gameMode;
if (userId && gameMode) {
   var myCreateLobbyParameter = new CreateLobbyParameter {
      userId = userId,
      gameMode = gameMode
   }
}

Then you have a real CreateLobbyParameter object to work with, or you can do whatever with a non-conforming argument.

edited Dec 27, 2017 at 16:20

answered Dec 27, 2017 at 16:07

Dan Schnau

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3 Comments

Talha Talip Açıkgöz Over a year ago

I have noImplicitAny option turned on, but let me try to adapt the code.

Talha Talip Açıkgöz Over a year ago

This worked out, when I gave any types to them, thanks for helping.

Dan Schnau Over a year ago

Happy to help :)

Talha Talip Açıkgöz · Accepted Answer · 2017-12-27 16:33:29Z

0

I actually found another way:

export function isSimilar(object: any, target: any): boolean {
    if (typeof(object) !== object && (typeof(object) !== typeof(target))) {
        return true;
    }
    const keys: string[] = Object.keys(object);
    const targetKeys: string[] = Object.keys(target);
    return !keys.every(x => targetKeys.indexOf(x) >= 0);
}

Usage:

hasNull(args, new CreateLobbyParameter());

edited Dec 27, 2017 at 16:33

answered Dec 27, 2017 at 16:28

Talha Talip Açıkgöz

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