Angular CLI - Typescript throws: Cannot read property 'length' of undefined

Question

I run in angular 4 project with ng serve and i get error

Cannot read property \'length\' of undefined

but I don\'t have any property length in

Answer 1

Could be bad path to component templateUrl, perhaps missing the ./

Before: templateUrl: 'my-control.component.html',

After: templateUrl: './my-control.component.html',