typescript define function as variable code example

Example 1: how to declare variable in typescript

const variableSample: number = 0;
let variableSample: number = 0;

Example 2: 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());