Some useful TS types I come across

useful-types.ts

/**
 * This is the generic type useful for declaring a nominal type,
 * which does not structurally matches with the base type and
 * the other types declared over the same base type
 *
 * Usage:
 * @example
 * type Index = Nominal<number, 'Index'>;
 * // let i: Index = 42; // this fails to compile
 * let i: Index = 42 as Index; // OK
 * @example
 * type TagName = Nominal<string, 'TagName'>;
 */
 type Nominal<T, Name extends string> = T & {
   [Symbol.species]: Name
 }