使用IO-TS将JS字符串数组转换为联合

我正在使用io-ts，我想知道是否有办法将字符串数组（文字）转换为此类文字的并集。例如：

export const CONTROLS = [
  "section",
  "text",
  "richtext",
  "number",
];

export const ControlType = t.union(
  // What to do here? Is this even possible? This is what came to mind but it's obviously wrong.
  // CONTROL_TYPES.map((type: string) => t.literal(type))
);

我不知道这是否可行，但鉴于这io-ts只是 JS 函数，我不明白为什么不可以。我只是不知道如何。

这种情况下的最终结果应该是（使用 io-ts）：

export const ControlType = t.union(
  t.literal("section"),
  t.literal("text"),
  t.literal("richtext"),
  t.literal("number"),
);

回答

export const CONTROLS = [
    "section",
    "text",
    "richtext",
    "number",
] as const;

function keyObject<T extends readonly string[]>(arr: T): { [K in T[number]]: null } {
    return Object.fromEntries(arr.map(v => [v, null])) as any
}

const ControlType = t.keyof(keyObject(CONTROLS))