unionOfArraysFilterCall.ts(25,50): error TS18048: 'item.id' is possibly 'undefined'.


==== unionOfArraysFilterCall.ts (1 errors) ====
    interface Fizz {
        id: number;
        fizz: string;
    }
    
    interface Buzz {
        id: number;
        buzz: string;
    }
    
    ([] as Fizz[] | Buzz[]).filter(item => item.id < 5);
    ([] as Fizz[] | readonly Buzz[]).filter(item => item.id < 5); 
    
    ([] as Fizz[] | Buzz[]).find(item => item);
    declare function isFizz(x: unknown): x is Fizz;
    ([] as Fizz[] | Buzz[]).find(isFizz);
    declare function isBuzz(x: unknown): x is Buzz;
    ([] as Fizz[] | Buzz[]).find(isBuzz);
    
    ([] as Fizz[] | Buzz[]).every(item => item.id < 5);
    
    ([] as Fizz[] | Buzz[]).reduce(item => item);
    
    
    ([] as [Fizz] | readonly [Buzz?]).filter(item => item?.id < 5);
                                                     ~~~~~~~~
!!! error TS18048: 'item.id' is possibly 'undefined'.