add func

packages/core/signal.mjs

@@ -7,7 +7,8 @@ This program is free software: you can redistribute it and/or modify it under th
 import { Hap } from './hap.mjs';
 import { Pattern, fastcat, reify, silence, stack, register } from './pattern.mjs';
 import Fraction from './fraction.mjs';
-import { id, _mod, clamp, objectMap } from './util.mjs';
+
+import { id, _mod, clamp, objectMap, getCurrentKeyboardState } from './util.mjs';
 
 export function steady(value) {
   // A continuous value
@@ -831,3 +832,27 @@ export const never = register('never', function (_, pat) {
 export const always = register('always', function (func, pat) {
   return func(pat);
 });
+
+/**
+ *
+ * Do something on a keypress, or array of keypresses
+ *
+ * @name onKey
+ * @memberof Pattern
+ * @returns Pattern
+ * @example
+ *  * s("bd(5,8)").onKey("Control:j", x => x.segment(16).color("red")).onKey("Control:i", x => x.fast(2).color("blue"))
+ */
+
+export const onKey = register('onKey', function (input, func, pat) {
+  if (Array.isArray(input) === false) {
+    input = [input];
+  }
+
+  const keyState = getCurrentKeyboardState();
+
+  const on = input.every((x) => {
+    return keyState[x];
+  });
+  return pat.when(on, func);
+});

packages/core/util.mjs

@@ -434,6 +434,25 @@ function getUnixTimeSeconds() {
   return Date.now() * 0.001;
 }
 
+let keyState;
+
+export function getCurrentKeyboardState() {
+  if (keyState == null) {
+    keyState = {};
+    // Listen for the keydown event to mark the key as pressed
+    window.addEventListener('keydown', (event) => {
+      keyState[event.key] = true; // Mark the key as pressed
+    });
+
+    // Listen for the keyup event to mark the key as released
+    window.addEventListener('keyup', (event) => {
+      keyState[event.key] = false; // Mark the key as released
+    });
+  }
+
+  return { ...keyState }; // Return a shallow copy of the key state object
+}
+
 // Floating point versions, see Fraction for rational versions
 // // greatest common divisor
 // export const gcd = function (x, y, ...z) {