core.js:4117 ERROR TypeError: Constructor cannot be invoked without 'new' about polytype HOT 8 CLOSED

Thanks for the report. You may be able to solve this by setting the target compiler option to "ES2015" or preferably "ES2020" in your tsconfig.json. Newer versions of @angular/cli have this set by default when a project is created with ng new.

{
  "compilerOptions": {
    ...
    "target": "es2015",
    ...
  }
}

Without that setting TypeScript will transpile Polytype to ES3, which doesn't work well for a number of reasons. Granted, the error message could be better.

from polytype.

I was using es5. I have changed it to es2020 but that caused other issues. I made both the target and the lib in tsconfig the same - es2017- and everything seems fine now. Thanks

from polytype.

Although the app runs with the above tsconfig specs, it will not build - it only builds with 'target': es5 - but this then is not compatible with your package. I am in a bind because of these two things. The failure to build with the above specs is not due to your package - it seems to be a more generalised problem with angular. If you find a solution please let me know, because this will also impact the use of your package.

By the way transpilation is to es5 in my case, not es3.

from polytype.

Actually Angular 9 should be fine with any JS target version, but you may need to change other settings, too.

It is also possible that some dependencies involved in the build process don't support ES6.
If you can spot which one they are, maybe from some error message, you may be able to update or replace them.

Another option is to import/include Polytype as an external dependency rather than have it bundled with the rest of the code. If you can do it you could keep targeting ES5 in TypeScript and copy the Polytype package folder unchanged into your dist folder.

Finally, if ES5 is required for compatibility with old browsers, then Polytype may not be the right tool for you. In this case mixins may be a more appropriate choice.

This is very generic advice but it's all I can think of without more detailed info, and porting Polytype to ES5 is not an option. Please, let me know if you manage to solve your problem in a way or another.

from polytype.

The problem is that the call to super() gets transpiled by TypeScript into Object.apply(...). But ES6 constructors require constructor semantics to be invoked (new ...).

If you know the arguments passed to every base constructor in advance, you can use a wrapper around the call to classes to enforce a new expression. In your example:

const PolyTypesComponentBase = classes(Utils);
const WrapPolyTypesComponentBase =
function () { return new PolyTypesComponentBase; } as unknown as typeof PolyTypesComponentBase;

...
export class PolyTypesComponent extends WrapPolyTypesComponentBase implements OnInit {

I'd call this a kind of a transpiler hack. It works as long as no additional functionality is needed.

from polytype.

from polytype.

Does it work with your old config with "target": "es5"?

from polytype.

Polytype 0.10 will fail to load if the module is transpiled to ES5 or ES3 code, and will throw an error with a message describing the problem instead. I'm going to close this issue by now. Let me know if you need more help.

from polytype.