typescript - 属性 'id' 在类型 'T' 上不存在。(2339)Typescript 泛型错误

Question

我有一个名为 updateArrayOfObjects 的函数它更新数组中的对象。我将一个泛型类型传递给这个函数，如下所示:

interface OtherIncomeSource {
  id?: string;
  incomeDescription?: string;
  amount?: number;
}

const otherIncomes = [
          {
            id: "#6523-3244-3423-4343",
            incomeDescription: "Rent",
            amount: 100
          },
          {
            id: "#6523-3244-3423-4343",
            incomeDescription: "Commercial",
            amount: undefined
    }
]

const updateArrayOfObjects = <T>(arrayOfObjects: T[], newObject: T, deleteObject: boolean = false): T[] => {
    const newArrayOfObjects = arrayOfObjects.slice();

  let index = newArrayOfObjects.findIndex((obj: T) => obj.id === newObject.id)
  if(deleteObject) {
    newArrayOfObjects.splice(index, 1);
  } else {
    if (index === -1) {
      newArrayOfObjects.push(newObject);
    } else {
      newArrayOfObjects[index] = newObject;
    }
  }

  return newArrayOfObjects
}

const newData = updateArrayOfObjects<OtherIncomeSource>(otherIncomes, {id: '1233', incomeDescription: 'agri', amount: 5000})

访问 id 时，我在下面提到的行中遇到错误说“属性 'id' 在类型 'T' 上不存在。(2339)”:

let index = newArrayOfObjects.findIndex((obj: T) => obj.id === newObject.id)

以下是此问题完整环境的 typescript 操场链接，此处错误以红色突出显示:Example in Typescript Playground

Answer 1

您需要为您的泛型类型提供如下约束:<T extends { id?: string }>
更新行 const updateArrayOfObjects = <T>(arrayOfObjects: T[], newObject: T, deleteObject: boolean = false): T[] => {
至 const updateArrayOfObjects = <T extends { id?: string }>(arrayOfObjects: T[], newObject: T, deleteObject: boolean = false): T[] => {