cup.ts

let working = true;

const coffee = {
  coffeeAmount: 10,

  drink: () => { coffee.coffeeAmount -= 5; },
  [Symbol.toPrimitive]() {
    return coffee.coffeeAmount === 0 ? "empty" : coffee.coffeeAmount
  },
  refill: () => {
    coffee.coffeeAmount += 5;
    coffeePot.coffeePotAmount -= 5;
  }
}

const work = {
  execute: () => { },
}

const coffeePot = {
  coffeePotAmount: 10,

  brew: () => { coffeePot.coffeePotAmount = 10; },
  [Symbol.toPrimitive]() {
    return coffeePot.coffeePotAmount === 0 ? "empty" : coffeePot.coffeePotAmount
  }
}

// code on the cup:

while (working) {
  coffee.drink();
  work.execute();
  if (coffee == "empty") {
    if (coffeePot == "empty")
      coffeePot.brew();
    coffee.refill();
  }
}

Runs w/ npx tsx cup.ts but vscode gives:
LN 34 This comparison appears to be unintentional because the types '{ coffeeAmount: number; drink: () => void; [Symbol.toPrimitive](): number | "empty"; refill: () => void; }' and 'string' have no overlap.

LN 35 This comparison appears to be unintentional because the types '{ coffeePotAmount: number; brew: () => void; [Symbol.toPrimitive](): number | "empty"; }' and 'string' have no overlap..