Split the module up into multiple files

src/features/toggle_secret_door.js

@@ -0,0 +1,12 @@
+import {settingsKey} from "../settings.js"
+
+// Toggles between normal and secret doors
+export function onDoorLeftClick(event) {
+	if (event.data.originalEvent.ctrlKey && game.user.isGM && game.settings.get(settingsKey, "toggleSecretDoors")) {
+		const types = CONST.WALL_DOOR_TYPES
+		const newtype = this.wall.data.door === types.DOOR ? types.SECRET : types.DOOR
+		this.wall.update({door: newtype})
+		return true
+	}
+	return false
+}