Callback
A function that is passed to another function as an argument to another function, which is called within an external function to complete some kind of routine or action.
interface definitionInterface {
(message: string): void;
}
const greeting = (message: string) => console.log(`Hello ${message}`);
const sayHello = (callback: definitionInterface) => {
callback('World!');
};
sayHello(greeting);
The example above is of a synchronous callback, since it is executed immediately.
