Uncaught TypeError: Class constructor LitElement cannot be invoked without 'new'

I’m trying out Lit Element in a vanilla Angular 6 project and running into Uncaught TypeError: Class constructor LitElement cannot be invoked without 'new' when trying out the hello world lit element example. This commit shows how I added webcomponentjs / litelement packages, allow custom schema in angular, declare the my-element LitElement example, and then use that element in the app. That commit was made right after running the ng new command.

If you want to poke at it, run the following commands…

git clone https://github.com/rjsteinert/angular-with-lit-element.git
cd angular-with-list-element
npm install
npm start

[daniel-nagy]

To anyone else that ends up here, lit-element is distributed as es2015 so you must transpile it to es5 as part of your build process. If you’re using Webpack add the following to your JavaScript rule:

{
  include: [
    // These packages are distributed as es2015 modules, therefore they need
    // to be transpiled to es5.
    /node_modules(?:\/|\\)lit-element|lit-html/
  ]
}

[dkundel]

Hey @rjsteinert,

do you need it to be downtranspiled to ES5? I changed my tsconfig.json to target ES2015 and then using the polyfill without the adapter works. You can see an example here: https://github.com/dkundel/vote-my-talk/commit/8b7f29a2993076b05582914b594b9500d67d919b

Cheeers, Dominik