Typescript元组类型映射不起作用：缺少默认数组属性

如何解决Typescript元组类型映射不起作用：缺少默认数组属性

我想创建一个将形状为[...T[]]的元组映射为[...TodoStepBlueprint<T>[]]的类型。

我对打字稿的了解有限，但我想我了解到目前为止所做的事情。

这是我到目前为止所拥有的：（是How to 'map' a Tuple to another Tuple type in Typescript 3.0的扩展），使用打字稿（3.7.5）

interface Strategy<T extends [...TodoStepBlueprint<AbstractTodoData>[]]> {}

type MaybeType<T> = T extends AbstractTodoData ? TodoStepBlueprint<T> : never;
type MaybeTypes<Tuple extends [...AbstractTodoData[]]> = {
  [Index in keyof Tuple]: MaybeType<
    Extract<Tuple[Index],[...AbstractTodoData[]]>
  >;
} & { length: Tuple["length"] };


interface TodoStepBlueprint<
  T extends AbstractTodoData,K = [...AbstractTodoData[]]
> {
  readonly todoType: Constructor<T>;
  readonly name: string;
  readonly possibleNext?: Strategy<MaybeTypes<K>>;
  // naming identifier
}

这会产生打字错误：

Type 'MaybeTypes<K>' does not satisfy the constraint 'TodoStepBlueprint<AbstractTodoData,AbstractTodoData[]>[]'.
  Type 'MaybeTypes<K>' is missing the following properties from type 'TodoStepBlueprint<AbstractTodoData,AbstractTodoData[]>[]': pop,push,concat,join,and 25 more.ts(2344)

某种程度上，打字稿不再理解它是一个数组。我做错了什么？

解决方法

感谢您的所有答复：

这是我的工作解决方案。

interface Strategy<T extends [...TodoStepBlueprint<AbstractTodoData>[]]> {
  getPossibleNext(): T;
  getNext(): T[number];
}

type EnsureTodoStepBlueprintType<T> = T extends AbstractTodoData
  ? TodoStepBlueprint<T>
  : never;

type MapToTodoStepBlueprintArrayType<Tuple extends any[]> = {
  [Index in keyof Tuple]: EnsureTodoStepBlueprintType<Tuple[Index]>;
} & { length: Tuple["length"] };

interface TodoStepBlueprint<
  TodoType extends AbstractTodoData,PossibleNextTodoTypes extends AbstractTodoData[] = []
> {
  readonly todoType: Constructor<TodoType>;
  readonly name: string;
  readonly possibleNext?: Strategy<
    MapToTodoStepBlueprintArrayType<PossibleNextTodoTypes>
  >;
  // naming identifier
}