🔢 fix: Unescape LaTeX Numbers in Artifact Content Edit (#10476)

packages/api/src/utils/latex.ts

@@ -0,0 +1,27 @@
+/**
+ * Unescapes LaTeX preprocessing done by the frontend preprocessLaTeX function.
+ * This reverses the escaping of currency dollar signs and other LaTeX transformations.
+ *
+ * The frontend escapes dollar signs for proper LaTeX rendering (e.g., $14 → \\$14),
+ * but the database stores the original unescaped versions. This function reverses
+ * that transformation to match database content.
+ *
+ * @param text - The escaped text from the frontend
+ * @returns The unescaped text matching the database format
+ */
+export function unescapeLaTeX(text: string | null | undefined): string | null | undefined {
+  if (!text || typeof text !== 'string') {
+    return text;
+  }
+
+  // Unescape currency dollar signs (\\$ or \$ → $)
+  // This is the main transformation done by preprocessLaTeX for currency
+  let result = text.replace(/\\\\?\$/g, '$');
+
+  // Unescape mhchem notation if present
+  // Convert $$\\ce{...}$$ back to $\ce{...}$
+  result = result.replace(/\$\$\\\\ce\{([^}]*)\}\$\$/g, '$\\ce{$1}$');
+  result = result.replace(/\$\$\\\\pu\{([^}]*)\}\$\$/g, '$\\pu{$1}$');
+
+  return result;
+}