Somtimes your extension does not work as expected. Here are some things you should do

1. Use your favorite browser

The browser that is built in in desktop might cache your extension files, so it is not really suited for extension development. Also in a browser you have better tools for troubleshooting and debugging. I use Google Chrome, since I think the developer tools are pretty good, but other browsers also have developer tools.

2. Look in the browser console

The console shows you if something goes wrong in your javascript code, some files are not found etc, so this is in most cases the first place to look for errors.

3. Turn off caching

When you are doing extension development the cache is your enemy: caching might mean that you are actually running an older version of your extension than you think. In Chrome you can turn it off in developer tools, in the network tab:



Note that the cache will only be disabled if you have developer tools open, so you should keep them open when developing.

4. Use the developer tools to look at your source code

Open your source code in the browsers developer tools:


Verify that this is the correct version.

5. Use the debugger to step through your code

The developer tools includes a very good debugger. Use it! Good places to set a breakpoint would be:

  • paint method
  • any methods triggered by an event (click etc)
  • callback methods

Note that you can also see the contents of structures like the layout and evaluate expressions used. And, of course step through your code.

6. Verify that you have only one copy of your extension under Extensions folder

Filenames of your qext file needs to be unique. If you are developing on Qlik Sense desktop it is your own responsibility to make sure that this is the case. If you make backup copies of your extension, do not save them under MyDocuments/Qlik/Sense/Extensions.

This post was originally published in Qlik Community: