chore: exclude zero from the set of allowed codepoints

Author: aradzie

packages/keybr-keyboard/lib/keycharacters.test.ts

@@ -11,62 +11,22 @@ test("codepoint characters", () => {
     /* "b" */ 0x0062,
     null,
   );
-  assert.strictEqual(
-    characters.getCodePoint(KeyModifier.None),
-    /* "a" */ 0x0061,
-  );
-  assert.strictEqual(
-    characters.getCodePoint(KeyModifier.Shift),
-    /* "a" */ 0x0061,
-  );
-  assert.strictEqual(
-    characters.getCodePoint(KeyModifier.Alt),
-    /* "b" */ 0x0062,
-  );
-  assert.strictEqual(
-    characters.getCodePoint(KeyModifier.ShiftAlt),
-    /* "b" */ 0x0062,
-  );
-});
-
-test("dead characters", () => {
-  const characters = new KeyCharacters(
-    "KeyA",
-    { dead: /* "*" */ 0x002a },
-    { dead: /* "*" */ 0x002a },
-    null,
-    null,
-  );
-  assert.strictEqual(characters.getCodePoint(KeyModifier.None), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Shift), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Alt), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.ShiftAlt), 0x0000);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.None), 0x0061);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.Shift), 0x0061);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.Alt), 0x0062);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.ShiftAlt), 0x0062);
 });
 
-test("special characters", () => {
+test("dead, special and ligature characters", () => {
   const characters = new KeyCharacters(
     "KeyA",
-    { special: /* "a" */ 0x0061 },
-    { special: /* "b" */ 0x0062 },
-    null,
-    null,
-  );
-  assert.strictEqual(characters.getCodePoint(KeyModifier.None), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Shift), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Alt), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.ShiftAlt), 0x0000);
-});
-
-test("ligature characters", () => {
-  const characters = new KeyCharacters(
-    "KeyA",
-    { ligature: "XX" },
-    { ligature: "YY" },
-    null,
-    null,
-  );
-  assert.strictEqual(characters.getCodePoint(KeyModifier.None), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Shift), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.Alt), 0x0000);
-  assert.strictEqual(characters.getCodePoint(KeyModifier.ShiftAlt), 0x0000);
+    /* "a" */ 0x0061,
+    { dead: /* COMBINING GRAVE ACCENT */ 0x0300 },
+    { special: /* ZERO WIDTH NON-JOINER */ 0x200c },
+    { ligature: "XYZ" },
+  );
+  assert.strictEqual(characters.getCodePoint(KeyModifier.None), 0x0061);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.Shift), null);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.Alt), null);
+  assert.strictEqual(characters.getCodePoint(KeyModifier.ShiftAlt), null);
 });

packages/keybr-keyboard/lib/keycharacters.ts

@@ -26,34 +26,55 @@ export class KeyCharacters {
     return isObject(ch) && "ligature" in ch;
   };
 
+  readonly id: KeyId;
+  readonly a: Character | null;
+  readonly b: Character | null;
+  readonly c: Character | null;
+  readonly d: Character | null;
+
   constructor(
-    readonly id: KeyId,
-    readonly a: Character | null,
-    readonly b: Character | null,
-    readonly c: Character | null,
-    readonly d: Character | null,
-  ) {}
-
-  getCodePoint(modifier: KeyModifier): CodePoint | 0x0000 {
-    const a = KeyCharacters.isCodePoint(this.a) ? this.a : null;
-    const b = KeyCharacters.isCodePoint(this.b) ? this.b : null;
-    const c = KeyCharacters.isCodePoint(this.c) ? this.c : null;
-    const d = KeyCharacters.isCodePoint(this.d) ? this.d : null;
+    id: KeyId,
+    a: Character | null,
+    b: Character | null,
+    c: Character | null,
+    d: Character | null,
+  ) {
+    this.id = id;
+    this.a = a || null;
+    this.b = b || null;
+    this.c = c || null;
+    this.d = d || null;
+  }
+
+  getCodePoint(modifier: KeyModifier): CodePoint | null {
     switch (modifier) {
       case KeyModifier.None:
-        return a ?? 0x0000;
+        return select(this.a);
       case KeyModifier.Shift:
-        return b ?? a ?? 0x0000;
+        return select(this.b, this.a);
       case KeyModifier.Alt:
-        return c ?? b ?? a ?? 0x0000;
+        return select(this.c, this.b, this.a);
       case KeyModifier.ShiftAlt:
-        return d ?? c ?? b ?? a ?? 0x0000;
+        return select(this.d, this.c, this.b, this.a);
       default:
         throw new Error();
     }
   }
 
   get valid() {
-    return this.a || this.b || this.c || this.d;
+    return Boolean(this.a || this.b || this.c || this.d);
+  }
+}
+
+function select(...characters: (Character | null)[]): CodePoint | null {
+  for (const character of characters) {
+    if (character != null) {
+      if (KeyCharacters.isCodePoint(character)) {
+        return character;
+      } else {
+        break;
+      }
+    }
   }
+  return null;
 }

packages/keybr-textinput-events/lib/emulation.ts

@@ -115,7 +115,7 @@ function fixKey(
   const characters = keyboard.getCharacters(code);
   if (characters != null) {
     key = String.fromCodePoint(
-      (codePoint = characters.getCodePoint(toKeyModifier(modifiers))),
+      (codePoint = characters.getCodePoint(toKeyModifier(modifiers)) ?? 0x0000),
     );
   }
   return [{ type, timeStamp, code, key, modifiers }, codePoint];