From bd40a662777f5d6e4fcee812baebdd170f00bbce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Benoi=CC=82t=20Rouleau?= <benoit.rouleau@icloud.com>
Date: Fri, 30 Oct 2026 13:08:44 -0400
Subject: [PATCH] js: report Cmd, and release keys the browser never says came
 up

Browsers name the Cmd and Windows keys `MetaLeft` and `MetaRight`, and
gl.js only knew their old names, `OSLeft` and `OSRight`, which Firefox
dropped in version 118, so `KeyCode::LeftSuper` never went down and
key events never held `KeyMods::logo`: Cmd+Z reached an app as Z. Both
names now map to Super, and `metaKey` sets the logo modifier.

macOS browsers send no keyup for a key released while Cmd is down, so
after Cmd+Z, Z stayed down until it was pressed again. Every key but
the modifiers now comes up with Cmd. A canvas that loses focus gets
none of its keys' keyups either, as when Cmd+Tab switches apps, so
they all come up with its focus.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 js/gl.js | 74 ++++++++++++++++++++++++++++++++++++++------------------
 1 file changed, 50 insertions(+), 24 deletions(-)

diff --git a/js/gl.js b/js/gl.js
index df0116ac9..ac1f40683 100644
--- a/js/gl.js
+++ b/js/gl.js
@@ -576,17 +576,50 @@ function into_sapp_keycode(key_code) {
         case "ShiftLeft": return 340;
         case "ControlLeft": return 341;
         case "AltLeft": return 342;
-        case "OSLeft": return 343;
+        // Cmd and the Windows key: "Meta" in every browser, and "OS" in
+        // Firefox before version 118.
+        case "MetaLeft": case "OSLeft": return 343;
         case "ShiftRight": return 344;
         case "ControlRight": return 345;
         case "AltRight": return 346;
-        case "OSRight": return 347;
+        case "MetaRight": case "OSRight": return 347;
         case "ContextMenu": return 348;
     }
 
     console.log("Unsupported keyboard key: ", key_code)
 }
 
+function into_sapp_modifiers(event) {
+    var modifiers = 0;
+    if (event.ctrlKey) {
+        modifiers |= SAPP_MODIFIER_CTRL;
+    }
+    if (event.shiftKey) {
+        modifiers |= SAPP_MODIFIER_SHIFT;
+    }
+    if (event.altKey) {
+        modifiers |= SAPP_MODIFIER_ALT;
+    }
+    if (event.metaKey) {
+        modifiers |= SAPP_MODIFIER_SUPER;
+    }
+    return modifiers;
+}
+
+// The keys the app was told went down, and not yet that they came up.
+var keys_down = new Set();
+
+// Tell the app the keys `released` picks came up, as browsers don't
+// always say.
+function release_keys(released, modifiers) {
+    keys_down.forEach(function (key) {
+        if (released(key)) {
+            keys_down.delete(key);
+            wasm_exports.key_up(key, modifiers);
+        }
+    });
+}
+
 function dpi_scale() {
     if (high_dpi) {
         return window.devicePixelRatio || 1.0;
@@ -1228,17 +1261,8 @@ var importObject = {
                         break;
                 }
 
-                var modifiers = 0;
-                if (event.ctrlKey) {
-                    modifiers |= SAPP_MODIFIER_CTRL;
-                }
-                if (event.shiftKey) {
-                    modifiers |= SAPP_MODIFIER_SHIFT;
-                }
-                if (event.altKey) {
-                    modifiers |= SAPP_MODIFIER_ALT;
-                }
-                wasm_exports.key_down(sapp_key_code, modifiers, event.repeat);
+                keys_down.add(sapp_key_code);
+                wasm_exports.key_down(sapp_key_code, into_sapp_modifiers(event), event.repeat);
                 // for "space", "quote", and "slash" preventDefault will prevent
                 // key_press event, so send it here instead
                 if (sapp_key_code == 32 || sapp_key_code == 39 || sapp_key_code == 47) {
@@ -1247,20 +1271,22 @@ var importObject = {
             };
             canvas.onkeyup = function (event) {
                 var sapp_key_code = into_sapp_keycode(event.code);
+                var modifiers = into_sapp_modifiers(event);
 
-                var modifiers = 0;
-                if (event.ctrlKey) {
-                    modifiers |= SAPP_MODIFIER_CTRL;
-                }
-                if (event.shiftKey) {
-                    modifiers |= SAPP_MODIFIER_SHIFT;
-                }
-                if (event.altKey) {
-                    modifiers |= SAPP_MODIFIER_ALT;
-                }
-
+                keys_down.delete(sapp_key_code);
                 wasm_exports.key_up(sapp_key_code, modifiers);
+                // macOS browsers send no keyup for a key released while Cmd
+                // is down, so every key but the modifiers (340 to 347),
+                // which do send one, comes up with Cmd.
+                if (sapp_key_code == 343 || sapp_key_code == 347) {
+                    release_keys(function (key) { return key < 340 || key > 347; }, modifiers);
+                }
             };
+            // Once the canvas loses focus, as when Cmd+Tab switches apps or
+            // Ctrl+Tab switches tabs, its keys come up elsewhere.
+            canvas.addEventListener("blur", function () {
+                release_keys(function () { return true; }, 0);
+            });
             canvas.onkeypress = function (event) {
                 var sapp_key_code = into_sapp_keycode(event.code);