Answers for ""Property 'note' has no initializer and is not definitely assigned in the constructor.","

Property 'firstName' has no initializer and is not definitely assigned in the constructor

"angularCompilerOptions": {
    //   ...
    "strictPropertyInitialization": false
    //   ...
  }

error TS2564: Property 'description' has no initializer and is not definitely assigned in the constructor. in angular class

id!: number;

got it, it's because typescript 2.7.2 included a strict class checking where all properties should be declared in constructor. So to work around that, just add a bang sign (!) like: name!:string;

Property has no initializer and is not definitely assigned in the constructor

@Component({...})
export class Component {
  @Input() myInput: string|undefined;
}

OR

@Component({...})
export class Component {
  @Input() myInput!: string;
}