type-samurai/src/to-primitive.d.ts

Advanced utility types for Typescript

/**
 * Turns accepted literal type argument to its primitive
 * @example
 * ```ts
 * // number
 * type Case1 = ToPrimitive<1>
 * // string
 * type Case2 = ToPrimitive<'1'>
 * // {a: number; b: string}
 * type Case3 = ToPrimitive<{a: 1;  b: 's'}>
 * ```
 */
export type ToPrimitive<T> = T extends string
  ? string
  : T extends number
  ? number
  : T extends null
  ? null
  : T extends undefined
  ? undefined
  : T extends boolean
  ? boolean
  : T extends bigint
  ? bigint
  : T extends symbol
  ? symbol
  : {
      [K in keyof T]: ToPrimitive<T[K]>;
    };