Function unwrap

lib/assert.ts:118–123

(x: T | undefined | null, message?: string, ...extra_info: any[])

}

export function unwrap<T>(x: T | undefined | null, message?: string, ...extra_info: any[]): T {
    if (x === undefined || x === null) {
        fail('Unwrap failed', message, extra_info);
    }
    return x;
}

// Take a type value that is maybe a string and ensure it is
// T is syntax sugar for unwrapping to a string union