How do I specify a data type when using a function expression to declare a class?

const Foo: new () => unknown = class {
  constructor() {}
  bar(): string {
    return ‘Hello World!’;
  }
};
const instance = new Foo();

I need to replace 'any' with 'unknown' below due to my configuration settings.

new () => unknown

Is there a way to define the result of Foo()?

Answer №1

My recommendation is to create an interface called Foo that corresponds to the instances generated by the class expression also named Foo:

interface Foo {
  bar(): string;
}

You can then define Foo as a type of new () => Foo:

const Foo: new () => Foo = class {
  constructor() { }
  bar(): string {
    return 'Hello World!';
  }
};

I hope this suggestion is helpful for you. Best of luck!

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