Utility function for checking if a key-combo is bound

examples/keybindings.js

@@ -39,3 +39,13 @@ function swapNeighbours() {
 function showNavigator() {
     Keybindings.bindkey("<Super>j", () => null, { opensNavigator: true })
 }
+
+// listFreeBindings("<super>").join("\n")
+function listFreeBindings(modifierString) {
+    let free = [];
+    const chars = "abcdefghijklmnopqrstuvxyz1234567890".split("")
+    const symbols = ["minus", "comma", "period", "plus"]
+    return [].concat(chars, symbols).filter(
+        key => Keybindings.getBoundActionId(modifierString+key) === 0
+    ).map(key => modifierString+key)
+}

keybindings.js

@@ -120,6 +120,15 @@ function openNavigatorHandler(actionName, keystr) {
     }
 }
 
+function getBoundActionId(keystr) {
+    let [dontcare, keycodes, mask] =
+        Gtk.accelerator_parse_with_keycode(keystr);
+    if(keycodes.length > 1) {
+        throw new Error("Multiple keycodes " + keycodes + " " + keystr);
+    }
+    const rawMask = devirtualizeMask(mask);
+    return global.display.get_keybinding_action(keycodes[0], rawMask);
+}
 
 function handleAccelerator(display, actionId, deviceId, timestamp) {
     const action = actionIdMap[actionId];