feat: validate PDF options with TDD tests

src/utils/pdf-options.ts

@@ -0,0 +1,88 @@
+const VALID_FORMATS = ["Letter", "Legal", "Tabloid", "Ledger", "A0", "A1", "A2", "A3", "A4", "A5", "A6"];
+const FORMAT_MAP = new Map(VALID_FORMATS.map(f => [f.toLowerCase(), f]));
+const PAGE_RANGES_RE = /^\d+(-\d*)?(\s*,\s*\d+(-\d*)?)*$/;
+const MARGIN_KEYS = new Set(["top", "right", "bottom", "left"]);
+
+type PdfInput = Record<string, any>;
+type ValidResult = { valid: true; sanitized: Record<string, any> };
+type InvalidResult = { valid: false; error: string };
+
+export function validatePdfOptions(opts: PdfInput): ValidResult | InvalidResult {
+  if (!opts || typeof opts !== "object") return { valid: true, sanitized: {} };
+
+  const sanitized: Record<string, any> = {};
+
+  // scale
+  if (opts.scale !== undefined) {
+    if (typeof opts.scale !== "number" || opts.scale < 0.1 || opts.scale > 2.0) {
+      return { valid: false, error: "scale must be a number between 0.1 and 2.0" };
+    }
+    sanitized.scale = opts.scale;
+  }
+
+  // format
+  if (opts.format !== undefined) {
+    if (typeof opts.format !== "string") {
+      return { valid: false, error: "format must be a string" };
+    }
+    const canonical = FORMAT_MAP.get(opts.format.toLowerCase());
+    if (!canonical) {
+      return { valid: false, error: `format must be one of: ${VALID_FORMATS.join(", ")}` };
+    }
+    sanitized.format = canonical;
+  }
+
+  // booleans
+  for (const field of ["landscape", "printBackground", "displayHeaderFooter", "preferCSSPageSize"]) {
+    if (opts[field] !== undefined) {
+      if (typeof opts[field] !== "boolean") {
+        return { valid: false, error: `${field} must be a boolean` };
+      }
+      sanitized[field] = opts[field];
+    }
+  }
+
+  // width/height
+  for (const field of ["width", "height"]) {
+    if (opts[field] !== undefined) {
+      if (typeof opts[field] !== "string") {
+        return { valid: false, error: `${field} must be a string (CSS dimension)` };
+      }
+      sanitized[field] = opts[field];
+    }
+  }
+
+  // margin
+  if (opts.margin !== undefined) {
+    if (typeof opts.margin !== "object" || opts.margin === null || Array.isArray(opts.margin)) {
+      return { valid: false, error: "margin must be an object with top/right/bottom/left string fields" };
+    }
+    for (const key of Object.keys(opts.margin)) {
+      if (!MARGIN_KEYS.has(key)) {
+        return { valid: false, error: `margin contains unknown key: ${key}` };
+      }
+      if (typeof opts.margin[key] !== "string") {
+        return { valid: false, error: `margin.${key} must be a string` };
+      }
+    }
+    sanitized.margin = { ...opts.margin };
+  }
+
+  // pageRanges
+  if (opts.pageRanges !== undefined) {
+    if (typeof opts.pageRanges !== "string") {
+      return { valid: false, error: "pageRanges must be a string" };
+    }
+    if (!PAGE_RANGES_RE.test(opts.pageRanges.trim())) {
+      return { valid: false, error: "pageRanges must match pattern like '1-5', '1,3,5', or '2-'" };
+    }
+    sanitized.pageRanges = opts.pageRanges;
+  }
+
+  // Pass through non-validated fields
+  for (const key of ["headerTemplate", "footerTemplate"]) {
+    if (opts[key] !== undefined) sanitized[key] = opts[key];
+  }
+
+  return { valid: true, sanitized };
+}