Mapped Types の as の解説を追加する

[suin]

例

const options = ["Fill", "Zoom", "Minimize", "DoNothing"] as const;

type Option = (typeof options)[number];
const mappings = {
  Fill: "Fill",
  Zoom: "Maximize",
  Minimize: "Minimize",
  DoNothing: "None",
} as const satisfies Record<Option, string>;

type Mapping = typeof mappings;

const reverseMappings = Object.fromEntries(
  Object.entries(mappings).map(([key, value]) => [value, key])
) as { [K in keyof Mapping as Mapping[K]]: K };