feat: Initial clean release of CHM

packages/editor/CodeMirror/extensions/selectedNoteIdExtension.ts

@@ -0,0 +1,27 @@
+import { Facet, StateEffect, StateField } from '@codemirror/state';
+
+// Allows updating the note ID stored in the state. Accessing the
+// note ID associated with the editor can be useful for plugins.
+export const setNoteIdEffect = StateEffect.define<string>();
+
+// Allows accessing the note ID
+export const noteIdFacet = Facet.define<string, string>({
+	combine: (possibleValues) => {
+		return possibleValues[0] ?? '';
+	},
+});
+
+const noteIdField = StateField.define({
+	create: () => '',
+	update: (oldValue, transaction) => {
+		for (const e of transaction.effects) {
+			if (e.is(setNoteIdEffect)) {
+				return e.value;
+			}
+		}
+		return oldValue;
+	},
+	provide: (field) => noteIdFacet.from(field),
+});
+
+export default [noteIdField];