icon-set.ts

// This Gist is created for the https://stackoverflow.com/questions/48774804/ StackOverflow question
interface Icon { src: string; }

interface IconSet {
  [iconName: string]: Icon;
}

type UiBuilder = <P, S extends IconSet>(iconRegistry: S) => {
  withIcon<K extends keyof S>(iconName: K): null,
};

const listIcons: IconSet = {
  sort: { src: 'sort.svg' }, // Expected to be OK
  email: { source: 'email.svg' }, // Expected to ERR
};

const profileIcons: IconSet = {
  security: { src: 'security.svg' }, // Expected to be OK
  email: { src: 'email.svg' }, // Expected to be OK
};

function buildUi(builder: UiBuilder) {
  builder(profileIcons).withIcon('security'); // Expected to be OK
  builder(profileIcons).withIcon('bold'); // Expected to ERR
}