refactor(editor): Move editor-ui and design-system to frontend dir (no-changelog) (#13564)

packages/frontend/editor-ui/src/components/HtmlEditor/utils.ts

@@ -0,0 +1,40 @@
+import type { Range } from './types';
+
+/**
+ * Return the ranges of a full range that are _not_ within the taken ranges,
+ * assuming sorted taken ranges. e.g. `[0, 10]` and `[[2, 3], [7, 8]]`
+ * return `[[0, 1], [4, 6], [9, 10]]`
+ */
+export function nonTakenRanges(fullRange: Range, takenRanges: Range[]) {
+	const found = [];
+
+	const [fullStart, fullEnd] = fullRange;
+	let i = fullStart;
+	let curStart = fullStart;
+
+	takenRanges = [...takenRanges];
+
+	while (i < fullEnd) {
+		if (takenRanges.length === 0) {
+			found.push([curStart, fullEnd]);
+			break;
+		}
+
+		const [takenStart, takenEnd] = takenRanges[0];
+
+		if (i < takenStart) {
+			i++;
+			continue;
+		}
+
+		if (takenStart !== fullStart) {
+			found.push([curStart, i - 1]);
+		}
+
+		i = takenEnd + 1;
+		curStart = takenEnd + 1;
+		takenRanges.shift();
+	}
+
+	return found;
+}