Use TypeScript function in javascript code example

Example 1: typescript function

// Parameter type annotation
function greet(name: string): string {
 return name.toUpperCase();
}

console.log(greet("hello"));		// HELLO
console.log(greet(1));				// error, name is typed (string)

Example 2: typescript function type

interface Date {
  toString(): string;
  setTime(time: number): number;
  // ...
}

Example 3: types function typescript

interface Easy_Fix_Solution {
    title: string;
    callback: Function;
}