const x = {
  foo: {inner: 3},
  bar: {inner: 'hi'},
};

const y = {
  inner: 3,
  inner: 'hi',
};

import { mapValues } from 'lodash';
const y: Y = mapValues(x, (z) => z.inner);

const y: {
    foo: string | number;
    bar: string | number;
}

const y: {
  foo: number;
  bar: string;
};