How to define a generic Type Guard in Typescript?

I want to define an interface for my classes that contains a isValidConfig function to be used as type guard. But I am not sure how to declare it.

I have done this:

type AnyConfig = ConfigA | ConfigB | ConfigC;

public abstract isValidConfig<T extends AnyConfig>(config: AnyConfig): config is T;



and

public abstract isValidConfig<T = AnyConfig>(config: T): config is T;


But I always get errors in the implementation like:

public isValidConfig<T extends ConfigA >(config: T): config is T {
return config.type === TrainingTypes.A;
} /// Types of parameters 'config' and 'config' are incompatible.
Type 'T' is not assignable to type 'ConfigA '.


Is it possible to do this? I haven't found the way.

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