Challenges arise when dealing with generics in TypeScript

Question

Challenges arise when dealing with generics in TypeScript

I'm a beginner in TypeScript and I'm trying to write a method with a generic type argument similar to what you can do in .Net.

Here's the code snippet I've been working on:

class TestObject {
  Id: number;
  Truc: string;
  Machin: string;
}

export default
  {

    async FirstMethod(): Promise<TestObject> {
      return await this.TestMethodGen<TestObject>();
    },

    async TestMethodGen<T>(): Promise<T>  {
      // Json Deserialization other etc ...
      return <T>new Object();
    }
  }

However, I keep running into a TypeScript error TS2347 and I'm unsure of how to fix it.

TS2347 (TS) Untyped function calls may not accept type arguments.

https://i.sstatic.net/sYtwk.png

Thank you in advance for any assistance.

typescript

Answer 1

Answer №1

As stated in the TypeScript documentation.

When working with generics to create factories in TypeScript, it is important to reference class types using their constructor functions.

The code snippet below has been successfully tested on my system.

class TestObject {
    Id: number;
    Truc: string;
    Machin: string;
}

export default {
    async FirstMethod(): Promise<TestObject> {
        return await this.TestMethodGen(TestObject);
    },

    async TestMethodGen<T>(c: { new (): T }): Promise<T> {
        // Perform Json Deserialization and other operations ...
        return new c();
    }
};

Answer 2

As stated in the TypeScript documentation.

When working with generics to create factories in TypeScript, it is important to reference class types using their constructor functions.

The code snippet below has been successfully tested on my system.

class TestObject {
    Id: number;
    Truc: string;
    Machin: string;
}

export default {
    async FirstMethod(): Promise<TestObject> {
        return await this.TestMethodGen(TestObject);
    },

    async TestMethodGen<T>(c: { new (): T }): Promise<T> {
        // Perform Json Deserialization and other operations ...
        return new c();
    }
};

Challenges arise when dealing with generics in TypeScript

Answer №1

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