Lodash使用Typescript进行缩减-没有重载匹配此调用

Question

Typscript的新手。

尝试使用Lodash进行简单的归约，

let collectionScenes: IScene[] = reduce(
  scenes,
  (prev, scene) =>
    scene.collectionId === action.collectionId
      ? prev.push(scene)
      : prev,
  [],
)

发生这次崩溃：

(19,41): No overload matches this call.
  Overload 1 of 6, '(collection: IScene[], callback: MemoListIterator<IScene, any[], IScene[]>, accumulator: any[]): any[]', gave the following error.
    Argument of type 'IKeyArray<IScene>' is not assignable to parameter of type 'IScene[]'.
      Type 'IKeyArray<IScene>' is missing the following properties from type 'IScene[]': length, pop, push, concat, and 26 more.
  Overload 2 of 6, '(collection: List<IScene>, callback: MemoListIterator<IScene, any[], List<IScene>>, accumulator: any[]): any[]', gave the following error.
    Argument of type 'IKeyArray<IScene>' is not assignable to parameter of type 'List<IScene>'.
      Property 'length' is missing in type 'IKeyArray<IScene>' but required in type 'List<IScene>'.
  Overload 3 of 6, '(collection: IKeyArray<IScene>, callback: MemoObjectIterator<IScene, any[], IKeyArray<IScene>>, accumulator: any[]): any[]', gave the following error.
    Type 'number | any[]' is not assignable to type 'any[]'.
      Type 'number' is not assignable to type 'any[]'.

有人可以让我知道此错误的原因以及如何解决该错误吗？

Answer 1

您的减速器有问题：

(prev, scene) =>
  scene.collectionId === action.collectionId
   ? prev.push(scene)
     ^^^^^^^^^^^^^^^^
   : prev

Array#push返回一个数字。这是数组的新长度：

const arr = ["a", "b", "c"];

console.log(arr.length);
console.log(arr.push("d"));
console.log(arr.push("e"));

因此，在reduce的下一次迭代中，累加器prev的值等于数组中 not 的数字。

您需要添加一个值并仍然返回一个数组：

prev.push(scene);
return prev;

但是，由于在条件运算符中这很麻烦，因此，如果使用，则可以使加法成为单个表达式：

Array#concat

(prev, scene) =>
  scene.collectionId === action.collectionId
   ? prev.concat(scene)
     ^^^^^^^^^^^^^^^^^^
   : prev

Spread syntax

(prev, scene) =>
  scene.collectionId === action.collectionId
   ? [...prev, scene]
     ^^^^^^^^^^^^^^^^
   : prev