How to import custom elements schema?
Importing custom elements schema allows an NgModule to contain non-Angular elements with dash case or element properties named with dash case.
To import CUSTOM_ELEMENTS_SCHEMA, add the following code to the file app.module.ts:
import {CUSTOM-ELEMENTS_SCHEMA} from '@angualar/core';
@NgModule({
schemas: [ CUSTOM-ELEMENTS_SCHEMA ]
})
export class AppModule {}