The migration between Shadow DOM V0 and V1 may be a painful task, especialy in large projects.
So, I wrote
Translate-ShadowDOM to automate many of the steps involved in upgrading.
Translate-ShadowDOM works for string as well as full DOM
That's why, you can use it as a tool to migrate you code base, as well as call it in runtime,
to addapt to unknown environment.
For example, you can use it to prepare you web components in V1 syntax and still make them work with old V0 Polyfills. Or otherwise, you can use it in V1 environment to support some legacy code. You will be able to make your vanilla JS custom elements "hybrid" like Polymer ones.
Install it with
npm install --save Translate-ShadowDOM or
bower install --save Translate-ShadowDOM
Then use the API,
Check out the README on github for a complete list of current and planned transformations, or check out the online migration demo bellow.