feat: Initial clean release of CHM

packages/editor/SelectionFormatting.ts

@@ -0,0 +1,73 @@
+// Stores information about the current content of the user's selection
+export interface MutableSelectionFormatting {
+	bolded: boolean;
+	italicized: boolean;
+	inChecklist: boolean;
+	inCode: boolean;
+	inUnorderedList: boolean;
+	inOrderedList: boolean;
+	inMath: boolean;
+	inLink: boolean;
+	spellChecking: boolean;
+	unspellCheckableRegion: boolean;
+
+	// Link data, both fields are null if not in a link.
+	linkData: {
+		readonly linkText: string|null;
+		readonly linkURL: string|null;
+	};
+
+	// If [headerLevel], [listLevel], etc. are zero, then the
+	// selection isn't in a header/list
+	headerLevel: number;
+	listLevel: number;
+
+	// Content of the selection
+	selectedText: string;
+}
+type SelectionFormatting = Readonly<MutableSelectionFormatting>;
+export default SelectionFormatting;
+
+export const defaultSelectionFormatting: SelectionFormatting = {
+	bolded: false,
+	italicized: false,
+	inChecklist: false,
+	inCode: false,
+	inUnorderedList: false,
+	inOrderedList: false,
+	inMath: false,
+	inLink: false,
+	spellChecking: false,
+	unspellCheckableRegion: false,
+
+	linkData: {
+		linkText: null,
+		linkURL: null,
+	},
+
+	headerLevel: 0,
+	listLevel: 0,
+
+	selectedText: '',
+};
+
+export const selectionFormattingEqual = (a: SelectionFormatting, b: SelectionFormatting): boolean => {
+	// Get keys from the default so that only SelectionFormatting key/value pairs are
+	// considered. If a and/or b inherit from SelectionFormatting, we want to ignore
+	// keys added by child interfaces.
+	const keys = Object.keys(defaultSelectionFormatting) as (keyof SelectionFormatting)[];
+
+	for (const key of keys) {
+		if (key === 'linkData') {
+			// A deeper check is required for linkData
+			if (a[key].linkText !== b[key].linkText || a[key].linkURL !== b[key].linkURL) {
+				return false;
+			}
+		} else if (a[key] !== b[key]) {
+			return false;
+		}
+	}
+
+	return true;
+};
+