js__typescript__pluralsight1/app/app.ts

function startGame() {
  // Starting a new game.
  let playerName: string = 'Audrey';
  logPlayer(playerName);

  const messagesElement: HTMLElement|null = document.getElementById('messages');
  if (messagesElement === null) {
    return;
  }
  messagesElement.innerText = 'Welcome to MultiMath! Starting a new game';
  console.log('Starting new game');
}

function logPlayer(name: string) {
  console.log(`New game starting for player: ${name}.`);
}

function arm(doc: HTMLDocument) {
  const startGameButton: HTMLElement|null = doc.getElementById('startGame');

  if (startGameButton) {
    startGameButton.addEventListener('click', startGame);
  }
}

arm(document);

// Type assertions (not casting, more like in Go).
let value: any = 42;
let fixedString1: string = (<number>value).toFixed(2);
let fixedString2: string = (value as number).toFixed(2);
console.log(value, fixedString1, fixedString2);