Desktop: Simplified and improve command service, and added command palette

- Commands "enabled" state is now expressed using a "when-clause" like in VSCode
- A command palette has been added to the Tools menu

ReactNativeClient/lib/services/commands/stateToWhenClauseContext.ts

@@ -0,0 +1,47 @@
+import { stateUtils } from 'lib/reducer';
+
+const BaseModel = require('lib/BaseModel');
+const Folder = require('lib/models/Folder');
+const MarkupToHtml = require('lib/joplin-renderer/MarkupToHtml');
+
+export default function stateToWhenClauseContext(state:any) {
+	const noteId = state.selectedNoteIds.length === 1 ? state.selectedNoteIds[0] : null;
+	const note = noteId ? BaseModel.byId(state.notes, noteId) : null;
+
+	return {
+		// UI elements
+		markdownEditorVisible: !!state.settings['editor.codeView'],
+		richTextEditorVisible: !state.settings['editor.codeView'],
+		markdownEditorPaneVisible: state.settings['editor.codeView'] && state.noteVisiblePanes.includes('editor'),
+		markdownViewerPaneVisible: state.settings['editor.codeView'] && state.noteVisiblePanes.includes('viewer'),
+		modalDialogVisible: !!Object.keys(state.visibleDialogs).length,
+		sideBarVisible: !!state.sidebarVisibility,
+		noteListHasNotes: !!state.notes.length,
+
+		// Application state
+		notesAreBeingSaved: stateUtils.hasNotesBeingSaved(state),
+		syncStarted: state.syncStarted,
+
+		// Current location
+		inConflictFolder: state.selectedFolderId === Folder.conflictFolderId(),
+
+		// Note selection
+		oneNoteSelected: !!note,
+		someNotesSelected: state.selectedNoteIds.length > 0,
+		multipleNotesSelected: state.selectedNoteIds.length > 1,
+		noNotesSelected: !state.selectedNoteIds.length,
+
+		// Note history
+		historyhasBackwardNotes: state.backwardHistoryNotes.length > 0,
+		historyhasForwardNotes: state.forwardHistoryNotes.length > 0,
+
+		// Folder selection
+		oneFolderSelected: !!state.selectedFolderId,
+
+		// Current note properties
+		noteIsTodo: note ? !!note.is_todo : false,
+		noteTodoCompleted: note ? !!note.todo_completed : false,
+		noteIsMarkdown: note ? note.markup_language === MarkupToHtml.MARKUP_LANGUAGE_MARKDOWN : false,
+		noteIsHtml: note ? note.markup_language === MarkupToHtml.MARKUP_LANGUAGE_HTML : false,
+	};
+}