I want to declare custom widget api in script

Where are you trying to use this exactly?  This will only work in widget jsm/server side files, if you are trying to do this in a js file or client script it won't work.

I created a jsm file and written the code but its not working. Can you provide a sample to create a jsm file with above code & config in my widget?

Does you extension work in a vm file?  Have you tried testing it in Widget Studio in the Script Sandbox (both Velocity and JavaScript Scripts can be tested there.

Additionally did you enable your new extension in administration?

I verified from script sandbox and vm file. It is working in both cases. But when I tried with script then only it is not working.Can you help me any other way please?? 

  Patrick Mason (pmason)

I enabled the extension but still I am not getting values from jsm file. Can you help me in other way please??

Instead of js file, I done the logic in vm and completed it.Thanks for everyone

Instead of js file, I done the logic in vm and completed it.Thanks for everyone