無法從物件內的物件串列中檢索正確的值

我對javascript很陌生，我一直在努力應對這種挑戰。我了解問題并實施了解決問題的邏輯，但我無法正確顯示這些值。

有人可以看看我的代碼并指出我正確的方向嗎？

const contacts = [
  {
    name: "Laurel",
    phone: "123 456 7890",
    email: "[email protected]",
    friends: ["Hardy", "Abbott", "Costello"],
  },
  {
    name: "Hardy",
    phone: "321 654 0987",
    email: "[email protected]",
    friends: ["Laurel", "Buster"],
  },
  {
    name: "Buster",
    phone: "987 654 3210",
    email: "[email protected]",
    friends: ["Hardy"],
  },
  {
    name: "Abbott",
    phone: "888 123 4567",
    email: "[email protected]",
    friends: ["Costello", "Laurel"],
  },
  {
    name: "Costello",
    phone: "767 676 7676",
    email: "[email protected]",
    friends: ["Abbott", "Laurel"],
  },
];

function findFriend(contacts, name, field) {
  let results = {};

  contacts.forEach(function (elm) {
// loop through all contacts and look for name
    if (elm.name === name) {
// select the first friend
      let friend = elm.friends[0];

      contacts.forEach((elm) => {
// looking for the friend in the contacts object
        if (elm.name === friend) {
// when found - this will get the required field and write it to the result
          results = elm[field]; 
        }
      });
    }
  });
  return results; // return the results
}

/

/ Test cases

console.log(findFriend(contacts, "Abbott", "phone")); // returns {name: "Costello", phone: "767 676 7676"}
console.log(findFriend(contacts, "Buster", "email")); // returns {name: "Hardy", email: "[email protected]"}
console.log(findFriend(contacts, "Bob", "phone")); // returns "Not found"
console.log(findFriend(contacts, "Costello", "birthday")); // returns "Not found"

uj5u.com熱心網友回復：

您應該更改results = elm[field];為if (elm[field]) { results[field] = elm[field]; results.name = elm.name; }，這是因為您需要驗證該屬性是否存在。如果 results 為空意味著在聯系人串列中未找到該朋友或未在該人中設定 searched 屬性，您還應該更改return results; 。return Object.keys(results).length ? results : "Not found";

const contacts = [
  {
    name: "Laurel",
    phone: "123 456 7890",
    email: "[email protected]",
    friends: ["Hardy", "Abbott", "Costello"],
  },
  {
    name: "Hardy",
    phone: "321 654 0987",
    email: "[email protected]",
    friends: ["Laurel", "Buster"],
  },
  {
    name: "Buster",
    phone: "987 654 3210",
    email: "[email protected]",
    friends: ["Hardy"],
  },
  {
    name: "Abbott",
    phone: "888 123 4567",
    email: "[email protected]",
    friends: ["Costello", "Laurel"],
  },
  {
    name: "Costello",
    phone: "767 676 7676",
    email: "[email protected]",
    friends: ["Abbott", "Laurel"],
  },
];

function findFriend(contacts, name, field) {
  let results = {};

  contacts.forEach(function (elm) {
    // loop through all contacts and look for name
    if (elm.name === name) {
      // select the first friend
      let friend = elm.friends[0];

      contacts.forEach((elm) => {
        // looking for the friend in the contacts object
        if (elm.name === friend) {
          // when found - this will get the required field and write it to the result
          if (elm[field]) {
            results[field] = elm[field];
            results.name = elm.name;
          }
        }
      });
    }
  });
  return Object.keys(results).length ? results : "Not found"; // return the results
}

console.log(findFriend(contacts, "Abbott", "phone")); // returns {name: "Costello", phone: "767 676 7676"}
console.log(findFriend(contacts, "Buster", "email")); // returns {name: "Hardy", email: "[email protected]"}
console.log(findFriend(contacts, "Bob", "phone")); // returns "Not found"
console.log(findFriend(contacts, "Costello", "birthday")); // returns "Not found"

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