TypeError: invalid ‘in’ operand obj

A weird JavaScript error that you may face when using Dojo Ajax for retrieving some JSON data from the server to render on the browser. This error happens because Dojo is unable to process the resulted JSON data which is the case when handleAs attribute is set to “text”.

In order to fix this error, set handleAs attribute to “json” instead of “text” as shown below in the example:

xhr.get({
	url: '/SomeServlet',
	handleAs: "json",
	timeout: 3000,
	load: function(data) { /* Success Handling */ },
	error: function(err) { /* Failure Handling */ }
});

This is my today’s two cent advice.

This entry was posted in Ajax, Dojo, Web 2.0 and tagged , , , , , by Hazem Saleh. Bookmark the permalink.

About Hazem Saleh

Hazem Saleh has more than eleven years of experience in Cloud, Mobile and Open Source technologies. He worked as a software engineer, technical leader, application architect, and technical consultant for many clients around the world. He is an Apache PMC (Project Management Committee) member and a person who spent many years of his life writing open source software. Beside being the author of the "JavaScript Unit Testing" book, "JavaScript Mobile Application Development" book, "Pro JSF and HTML5" book and the co-author of the "Definitive guide to Apache MyFaces" book, Hazem is also an author of many technical articles, a developerWorks contributing author and a technical speaker in both local and international conferences such as ApacheCon North America, Geecon, JavaLand, JSFDays, CON-FESS Vienna and JavaOne. Hazem is an XIBMer, he worked in IBM for ten years. Now, He is working for Nickelodeon New York as a Mobile Architect. He is also an OpenGroup Master Certified Specialist.