eventlog: add params for from and to date

src/validator.js

@@ -10,6 +10,14 @@ function isEmail(email) {
   return emailRegex.test(email);
 }
 
+function isIsoDate(value) {
+    assert.strictEqual(typeof value, 'string');
+
+    const date = new Date(value);
+    return !Number.isNaN(date.getTime());
+}
+
 export default {
-    isEmail
+    isEmail,
+    isIsoDate
 };