Exploring the concept of TypeScript interface declaration

I have a function A that will return function B. The parameter of function B is object C, which has a property named D with a type of T.

T's value is determined when function B is fetched; this means T can be set when calling function A or using alternative methods.

How should this be defined in TypeScript? Thank you very much.


I've attempted the following approach which does work. However, it's not exactly what I'm aiming for:

interface C<T> {
    d: T;
    e: number;
}

interface B<T> {
    (param: C<T>): void;
}

interface A<T> {
    (): B<T>;
}

const a: A<number> = () => ({d, e}) => {
    console.log(d, e)
};

What I'm looking for might resemble something like:

const a: A = () => ({d, e}) => {
    console.log(d, e)
};
const b1 = a<number>();
const b2 = a<string>();

I'm unsure about how to achieve this.

Answer №1

You're certainly headed in the right direction; personally, I prefer using types over interfaces for clarity:

interface C<T> {
    d: T;
    e: number;
}

type B<T> = (params: C<T>) => void

type A = <T>() => B<T>

// Alternatively, for a more concise approach: type A = <T>() => (params: C<T>) => void

const a: A = () => ({d, e}) => {
    console.log(d, e)
};

const withNumber = a<number>();
const withString = a<string>();

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