A registry is set using below command.
npm set registry http://www.thelittletechie.com:8080
To unset a registry type the below command in command prompt.
npm config edit
This opens a file in editor with the file name .npmrc which is the config file of npm.
Remove the registry line which you have set and save the file.
registry=http://www.thelittletechie.com:8080/
That’s it you have now removed the set registry.