diff --git a/src/headful.js b/src/headful.js
index <HASH>..<HASH> 100644
--- a/src/headful.js
+++ b/src/headful.js
@@ -47,6 +47,9 @@ headful.props = propertySetters;
  * Tests whether the given `props` object contains a property with the name of `propNameOrFunction`.
  */
 function noProp(props, propNameOrFunction) {
+    if (!props) {
+        throw new Error('Headful: You must pass all declared props when you use headful.props.x() calls.');
+    }
     const propName = typeof propNameOrFunction === 'function' ? propNameOrFunction.name : propNameOrFunction;
     return !props.hasOwnProperty(propName);
 }
Throw error when noProp() is being called without props argument