类型“ Array []”不可分配给类型“ [Array]” [英] Type 'Array[]' is not assignable to type '[Array]'

问题描述

在尝试获取打字稿时，此错误一直困扰着我。谁能解释两个数组之间的区别？这不是数组吗？如果不是，那是什么？

This error keeps bugging me while I'm trying to get a grab on typescript. Can anyone explain what is the difference between the two 'array'? Is any of this not an array? If not, what is it then?

[ts] Type 'AppointmentItemData[]' is not assignable to type '[AppointmentItemData]'.
       Property '0' is missing in type 'AppointmentItemData[]'.

推荐答案

您的第一种类型（ AppointmentItemData [] ）是 AppointmentItemData 元素的数组，而第二种类型是一个元组，该元组只能包含单个 AppointmentItemData 。引用文档：

Your first type (AppointmentItemData[]) is an array of AppointmentItemData elements, while your second type is a tuple, that may only ever contain a single AppointmentItemData. Quoting from the docs:

元组类型允许您表达一个数组，在该数组中已知固定数量的元素的类型，但不必相同。例如，您可能希望将值表示为一对字符串和数字：

// Declare a tuple type
let x: [string, number];
// Initialize it
x = ["hello", 10]; // OK
// Initialize it incorrectly
x = [10, "hello"]; // Error

Typescript可让您编码该变量应只有每个元素中都有3个元素的数组，其中第一个元素是数字，第二个元素是字符串，第三个元素是Promise，最终将解析为形状如 Lizard ，而如果不是编码 [数字，字符串，Promise< Lizard>] 的唯一方法将是 {} [ ] （大致是 Object [] ）。

Typescript allows you to encode that "this variable should only every have a 3 element array in it, where the first element is a number, the second is a string, and the third is a Promise that will eventually resolve to something shaped like a Lizard", whereas if it didn't the only way to encode [number, string, Promise<Lizard>] would be {}[] (that is, roughly, an Object[]).

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