强制数组在Typescript中至少具有一个值

Question

是否有一种Typescript方式要求数组至少需要一个值？例如：

type value = "1" | "2";

export interface ISomething {
  values: value[] // < should be required and have at least one.
}

Answer 1

尝试一下

type value = "1" | "2";

export interface ISomething {
  values: {
    0: value,
    [key: number]: value,
  }
}``

Answer 2

您还可以实现扩展Array的接口：

type value = "1" | "2";

interface IValueArray extends Array<value> {
  0: value; // ensure that at least one 'value' is present
}

export interface ISomething {
  values: IValueArray
}

const something1: ISomething = {
  values: ['1']
}

const something2: ISomething = {
  values: [] // type error
}