Capturing keyboard events for a limited time

Question

I'm trying to code a kind of simple video game where there are two kind of players:

• Human Players: They enter an keyboard input
• CPU Players: A random input is calculated

For Human Players there is a T round time and a T' input entering time. Let's say, if T=20 and T'=5, a player has 20 seconds to start typing, but only 5 seconds of typing time. So, if the player starts typing at T=10, will only be able to type those T'=5 seconds until T=15.

Just so you know, I'm using Typescript, and I had something like this in mind:

while (!gameOver) {
   // do some stuff like knowing who's player turn is it

   var enteredInput;

   if (player.isHuman()) {
      enteredInput = captureKeyboardInputsFor(seconds);
   } else {
      enteredInput = calculateRandomCPUPlayerInput();
   }

   // process input & do actions
}

What I would like to achieve here is a kind of synchronous typing process, I have the game logic well defined in mind, but I'm trying to figure out how can I do this keeping my loop game synchronous (as the players play in turns), using TypeScript.

I would really appreciate any kind of guidance, alternatives or ideas of possible ways of solving my concerns.