keyof in Typescript

Takes an object type and produces a string or numeric literal union of its keys.

import { Equal, Expect } from "../helpers/type-utils";
 
const testingFrameworks = {
  vitest: {
    label: "Vitest",
  },
  jest: {
    label: "Jest",
  },
  mocha: {
    label: "Mocha",
  },
};
 
type TestingFramework = keyof typeof testingFrameworks;
// type TestingFramework = "vitest" | "jest" | "mocha"

Links

• https://www.typescriptlang.org/docs/handbook/2/keyof-types.html