Make selected component accessible via browser console

[aflatscher-loop]

The old vue devtools (browser plugin) allowed to access the currently selected component instance via $vm in the browser console. This was quite handy if you wanted to trigger some exposed functions or similar. Are there any plans on bringing this feature back?

[webfansplz]

Good catch. I'll check it out when I have time, and if anyone is interested, PR is Welcome.