how to make a function parameter optional angular code example

Example 1: how to make a parameter optional in typescript

// Optional parameter
function foo(x?: number) {
    console.log("x : "+ x);
}
foo();
foo(6);

Example 2: How to pass optional parameters while omitting some other optional parameters?

export interface INotificationService {
    error(message: string, title?: string, autoHideAfter? : number);
}

class X {
    error(message: string, title?: string, autoHideAfter?: number) {
        console.log(message, title, autoHideAfter);
    }
}

new X().error("hi there", undefined, 1000);