fix: validate date

src/isValidDate.js

@@ -0,0 +1,17 @@
+"use strict";
+
+module.exports = function isValidDate(maybeDate) {
+  if (!maybeDate) {
+    return false;
+  }
+
+  if (!(maybeDate instanceof Date)) {
+    return false;
+  }
+
+  if (Number.isNaN(maybeDate.getTime())) {
+    return false;
+  }
+
+  return true;
+};

src/isValidDate.test.js

@@ -0,0 +1,17 @@
+"use strict";
+
+const test = require("ava");
+
+const isValidDate = require("./isValidDate");
+
+test("is valid date", (t) => {
+  t.true(isValidDate(new Date()));
+});
+
+test("is not empty date", (t) => {
+  t.false(isValidDate());
+});
+
+test("is not invalid date object", (t) => {
+  t.false(isValidDate(new Date("hello")));
+});

src/sitemapDateTime.js

@@ -1,11 +1,17 @@
 "use strict";
 
+const isValidDate = require("./isValidDate");
+
 module.exports = function sitemapDateTime(date) {
   if (!date) {
     return;
   }
 
   const dateObject = typeof date === "string" ? new Date(date) : date;
 
+  if (!isValidDate(dateObject)) {
+    return;
+  }
+
   return dateObject.toISOString();
 };