app,io: [js] change Shortcut key on macOS/iOS

Previously, the Shortcut key was hardcoded as ModCtrl. That
patches tries to identify the OS and change the key.

Fixes: https://todo.sr.ht/~eliasnaur/gio/624
Signed-off-by: Lucas Rodrigues <inkeliz@inkeliz.com>
Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/os_js.go

@@ -406,27 +406,12 @@ func (w *window) keyEvent(e js.Value, ks key.State) {
 	k := e.Get("key").String()
 
 	if n, ok := translateKey(k); ok {
-		isJSHandledEdit := false
-		switch n {
-		case key.NameDeleteBackward:
-			if w.tarea.Get("selectionStart").Int() > 0 {
-				isJSHandledEdit = true
-			}
-		case key.NameDeleteForward:
-			if w.tarea.Get("selectionStart").Int() < w.tarea.Get("value").Length() {
-				isJSHandledEdit = true
-			}
-		}
-
 		if ks == key.Press {
-			isMod := n == key.NameAlt || n == key.NameCommand || n == key.NameCtrl || n == key.NameShift
+			isMod := n == key.NameAlt || n == key.NameCommand || n == key.NameCtrl || n == key.NameShift || n == key.NameSuper
 			isFunc := n == key.NameUpArrow || n == key.NameDownArrow || n == key.NameLeftArrow || n == key.NameRightArrow ||
 				n == key.NamePageUp || n == key.NamePageDown || n == key.NameHome || n == key.NameEnd ||
-				n == key.NameEscape || n == key.NameReturn || n == key.NameEnter || n == key.NameTab
-
-			if !isJSHandledEdit && (n == key.NameDeleteBackward || n == key.NameDeleteForward) {
-				isFunc = true
-			}
+				n == key.NameEscape || n == key.NameReturn || n == key.NameEnter || n == key.NameTab ||
+				n == key.NameDeleteBackward || n == key.NameDeleteForward
 
 			if isMod || isFunc {
 				// Gio will request the browser to change the selection/carret position natively.
@@ -434,7 +419,6 @@ func (w *window) keyEvent(e js.Value, ks key.State) {
 			}
 		}
 
-		if !isJSHandledEdit {
 		cmd := key.Event{
 			Name:      n,
 			Modifiers: modifiersFor(e),
@@ -442,7 +426,6 @@ func (w *window) keyEvent(e js.Value, ks key.State) {
 		}
 		w.processEvent(cmd)
 	}
-	}
 }
 
 func (w *window) ProcessEvent(e event.Event) {
@@ -502,6 +485,12 @@ func modifiersFor(e js.Value) key.Modifiers {
 	if e.Call("getModifierState", "Shift").Bool() {
 		mods |= key.ModShift
 	}
+	if e.Call("getModifierState", "Meta").Bool() {
+		mods |= key.ModCommand
+	}
+	if e.Call("getModifierState", "OS").Bool() {
+		mods |= key.ModSuper
+	}
 	return mods
 }
 
@@ -522,6 +511,9 @@ func (w *window) touchEvent(kind pointer.Kind, e js.Value) {
 	if e.Get("ctrlKey").Bool() {
 		mods |= key.ModCtrl
 	}
+	if e.Get("metaKey").Bool() {
+		mods |= key.ModCommand
+	}
 	for i := 0; i < n; i++ {
 		touch := changedTouches.Index(i)
 		pid := w.touchIDFor(touch)
@@ -668,10 +660,9 @@ func (w *window) ReadClipboard() {
 	if w.clipboard.IsUndefined() {
 		return
 	}
-	if w.clipboard.Get("readText").IsUndefined() {
-		return
+	if w.clipboard.Get("readText").Truthy() {
+		w.clipboard.Call("readText").Call("then", w.clipboardCallback)
 	}
-	w.clipboard.Call("readText", w.clipboard).Call("then", w.clipboardCallback)
 }
 
 func (w *window) WriteClipboard(mime string, s []byte) {

io/key/mod.go

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: Unlicense OR MIT
 
-//go:build !darwin
-
+//go:build !darwin && !js
 package key
 
 // ModShortcut is the platform's shortcut modifier, usually the ctrl

io/key/mod_js.go

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package key
+
+import (
+	"strings"
+	"syscall/js"
+)
+
+// ModShortcut is the platform's shortcut modifier, usually the ctrl
+// modifier. On Apple platforms it is the cmd key.
+var ModShortcut = ModCtrl
+
+// ModShortcut is the platform's alternative shortcut modifier,
+// usually the ctrl modifier. On Apple platforms it is the alt modifier.
+var ModShortcutAlt = ModCtrl
+
+func init() {
+	nav := js.Global().Get("navigator")
+	if !nav.Truthy() {
+		return // Almost impossible to happen
+	}
+
+	platform := ""
+	if p := nav.Get("platform"); p.Truthy() {
+		platform = p.String()
+	}
+	platform = strings.ToLower(platform)
+
+	// Based on https://developer.mozilla.org/en-US/docs/Web/API/Navigator/platform#examples
+	for _, darwinPlatform := range []string{"mac", "iphone", "ipad", "ipod"} {
+		if strings.HasPrefix(platform, darwinPlatform) {
+			ModShortcut = ModCommand
+			ModShortcutAlt = ModAlt
+			return
+		}
+	}
+}