TypeScript. Enum/Union как ключ

export enum DetailStatus {
  IN_WAREHOUSE = 'in_warehouse',
  IN_SERVER = 'in_server',
  WRITTEN_OFF = 'written_off',
  RESERVED = 'reserved',
  REPAIR = 'under_repair',
  LABORATORY = 'in_laboratory',
  BROKEN = 'broken',
}

export type DetailType = 'cpu' | 'ram' | 'pci' | 'storage';

export type DetailCountInfo = {
  [type in DetailType]: {
    [status in DetailStatus]: number;
  };
};

Эквивалентно:

type DetailCountInfo = {
  cpu: {
      in_warehouse: number;
      in_server: number;
      written_off: number;
      reserved: number;
      under_repair: number;
      in_laboratory: number;
      broken: number;
  };
  ram: {
    in_warehouse: number;
    in_server: number;
    ... 4 more ...;
    broken: number;
  };
  pci: {
      ...;
  };
  storage: {
      ...;
  };
};