An argument for '_app' was not provided. typescript code example
Example: Expected 2 arguments, but got 1.ts(2554) core.d.ts(7888, 47): An argument for 'opts' was not provided.
This is because there is a synthax change in the new angular version.
@ViewChild("password", { static: true }) password: ElementRef;
@ViewChild("confirmPassword", { static: true }) confirmPassword: ElementRef;