Signals

A Signal is an event of your own. One part of a map says that something happened, such as a wave cleared, without knowing who listens: the shop, the score and the music each add a handler, and the wave code only emits.

import { Signal } from "trigscript/signals";

program(() => {
  const waveCleared = new Signal<number>();
  waveCleared.on((wave) => { setResources(P1, "add", 100 * wave, "ore"); });
  waveCleared.once(() => print("First wave down!"));            // First wave down!
  const id = waveCleared.on((wave) => print(`Wave ${wave} cleared`));   // Wave 1 cleared
  waveCleared.emit(1);
  waveCleared.off(id);
  waveCleared.emit(2);
});

A signal carries one value of the type it is made with: a number, a boolean, a text or a unit (new Signal<Unit>()). Its handlers are functions kept as values, and they run one after another, in the order they were added, within the frame. A handler that runs an action is written with braces, (wave) => { setResources(…); }, since a kept function cannot give back an action. Make the signal inside the program that uses it.