type AAndB = {
  a: string;
  b: string;
};

type Neither = {
  someOtherProp: string;
};

type Props = AAndB | Neither;

// This will throw a typescript compiler warning, as a is present without b
const example: Props = {
  a: 'something'
}

// These will pass the typescript compiler
const example2: Props = {
  a: 'something',
  b: 'something else',
};

const example3: Props = {
  someOtherProp: 'some other prop',
};