Question

我开始学习打字稿，所以我正在创建要解决的情况，但出现错误并不确定原因，请参见上面的代码：

interface IObjct {
  name: string,
  city: string,
  age: number,
}


const john = {
  name: "John",
  city: "London",
  age: 24
};

const jerry = {
 name: "Jerry",
 city: "Rome",
 age: 43
};

function filterPerson(arr: Array<IObjct>, term: string, key: string) {
  return arr.filter(function(person) {
    return person[key].match(term);
  });
}

我在网上遇到错误：return person [key] .match（term）;

person [key]

元素隐式地具有“ any”类型，因为类型“ string”的表达式不能用于索引类型“ IObjct”。

在类型“ IObjct”上未找到带有“字符串”类型参数的索引签名。ts（7053）

filterPerson([john, jerry], "London", "city");

Answer 1

我认为，这应该可以解决您的问题：

interface IObjct {
    name: string;
    city: string;
    age: number;
}


const john = {
    name: "John",
    city: "London",
    age: 24,
};

const jerry = {
    name: "Jerry",
    city: "Rome",
    age: 43,
};

function filterPerson(arr: IObjct[], term: string, key: string) {
    return arr.filter(function (person) {
        return person[key].match(term);
    });
}

Answer 2

您可以执行以下操作来检查类型：

interface IObjct {
  name: string,
  city: string,
  age: number,
 
}


const john = {
  name: "John",
  city: "London",
  age: 24
};

const jerry = {
 name: "Jerry",
 city: "Rome",
 age: 43
};

function filterPerson(arr: Array<IObjct>, term: string, key: keyof IObjct):Array<IObjct> {
  return arr.filter(function (person: IObjct) {
    const pers = person[key];
    if (typeof pers === "string") {
      return pers.match(term);
    }
    else {
      return false;
   }
  });
}

const results = filterPerson([john, jerry], "London", "city");
console.log(results);

表达式类型“字符串”不能用作索引类型

2 个答案: