snapshot of https://github.com/excalidraw/excalidraw.git (master, 2026-09-16; blobs > 131072B omitted)

packages/excalidraw/components/TTDDialog/utils/mermaidValidation.ts

@@ -0,0 +1,41 @@
+export const isValidMermaidSyntax = (content: string): boolean => {
+  const trimmed = content.trim();
+  if (!trimmed) {
+    return false;
+  }
+
+  const openBrackets = (trimmed.match(/\[/g) || []).length;
+  const closeBrackets = (trimmed.match(/\]/g) || []).length;
+  const openBraces = (trimmed.match(/\{/g) || []).length;
+  const closeBraces = (trimmed.match(/\}/g) || []).length;
+  const openParens = (trimmed.match(/\(/g) || []).length;
+  const closeParens = (trimmed.match(/\)/g) || []).length;
+
+  if (
+    openBrackets !== closeBrackets ||
+    openBraces !== closeBraces ||
+    openParens !== closeParens
+  ) {
+    return false;
+  }
+
+  const lastLine = trimmed.split("\n").pop()?.trim() || "";
+  const incompletePatterns = [
+    /-->$/,
+    /--$/,
+    /-\.$/,
+    /==>$/,
+    /==$/,
+    /~~$/,
+    /::$/,
+    /:$/,
+    /\|$/,
+    /&$/,
+  ];
+
+  if (incompletePatterns.some((pattern) => pattern.test(lastLine))) {
+    return false;
+  }
+
+  return true;
+};