creating a function in typescript code example

Example 1: typescript default parameter

// Default Parameters
sayHello(hello: string = 'hello') { 
    console.log(hello); 
}

sayHello(); // Prints 'hello'

sayHello('world'); // Prints 'world'

Example 2: types function typescript

interface Safer_Easy_Fix {
    title: string;
    callback: () => void;
}
interface Alternate_Syntax_4_Safer_Easy_Fix {
    title: string;
    callback(): void;
}

Example 3: typescript function as parameter

function createPerson(name: string, doAction: () => void): void {
  console.log(`Hi, my name is ${name}.`);
  doAction(); // doAction as a function parameter.
}

// Hi, my name is Bob.
// performs doAction which is waveHands function.
createPerson('Bob', waveHands());

Example 4: types function typescript

interface Param {
    title: string;
    callback: function;
}