index.ts

interface KeyVal {
  customerID: string;
  isLoggedIn: boolean;
  count: number;
}

const sensi = <T extends keyof KeyVal>(key: T, value: KeyVal[T]) => {

};

sensi('customerID', 'str');
sensi('customerId', 'str');
sensi('isLoggedIn', 'str');
sensi('isLoggedIn', true);
sensi('count', true);
sensi('count', 1);
sensi('foober', null);