error ""Failed to construct 'HTMLElement': Please use the 'new' operator"" when using with Angular/elements 8.2.0

error ""Failed to construct 'HTMLElement': Please use the 'new' operator"" when using with Angular/elements 8.2.0

[MikeVaz]

I believe the problem is how you transpile your ES2015 code in ES5 code. And it might be in NgElement code.

Transpilers VS 1.9
The version 1.9 of this polyfill does not patch browsers with full native support for Custom Elements, as anyone would expect from a polyfill based on features detection.

However, if your transpiler transforms native ES2015 classes into something incompatible, like TypeScript does in this case, you need to update, change, or better configure your tools to support proper classes.

Babel 7 should've solved this in core, so use Babel 7 if you need transpilers.

I would try to compare what is used in this angular module to deal with ES classes. Is it transpiled by Typescript or is it trying to do something custom to mimic classes. If it is a custom solution you'd probably want to fix it by applying similar pattern from Babel 7 to reflect ES classes in ES5 syntax better.

I know, it might be supper overwhelming for devs who are not JS nerds. But it is a side effect of frameworks and tools we use right now and extra unnecessary complexity we invited to our projects.

[WebReflection]

1.9 indeed doesn't care about broken transpilers do this is a won't fix.

You can use older versions from CDNs or update your transpiler or create bundles for modern browsers without transpiling classes.