Sometimes, we want to declare a delegate type in TypeScript.
In this article, we’ll look at how to declare a delegate type in TypeScript.
How to declare a delegate type in TypeScript?
To declare a delegate type in TypeScript, we can define an interface that restricts the signature and return type of a function.
For instance, we write
interface Greeter {
(message: string): void;
}
const sayHi = (greeter: Greeter) => {
greeter("Hello!");
};
sayHi((msg) => console.log(msg));
to define the Greeter interface that has signature (message: string) and has the void return type.
Then we set the greeter parameter of the sayHi function to the Greeter type.
Therefore, greeter takes a string and returns nothing.
Conclusion
To declare a delegate type in TypeScript, we can define an interface that restricts the signature and return type of a function.
