javascript - 使用递归进行深度对象比较

Question

我尝试使用递归进行深度对象比较，但我的函数返回 undefined。

我知道有更好的方法来比较对象(IE JSON.Stringify())，但我不明白为什么我的函数返回 undefined。

function deepObjCompare(obj1, obj2) {

  Object.keys(obj1).forEach((key) => {
    const key1 = obj1[key];
    const key2 = obj2[key];

    if (key2) {
      if (typeof key1 === "object" && key1 !== null) {
        deepObjCompare(key1, key2);
      } else if (key1 === key2) {
        return true;
      }
    }
    return false;
  });
}

const obj1 = {
  name: "Bill",
  address: {
    cityNow: "Paris",
    cityFuture: "NYC"
  },
  age: 39
};

const obj2 = {
  name: "Bill",
  address: {
    cityNow: "Paris",
    cityFuture: "NYC"
  },
  age: 39
};

const obj3 = {
  name: "Bob",
  address: "Paris",
  age: 39
};

console.log(deepObjCompare(obj1, obj3));

Answer 1

我在这里看到三个主要问题:

• deepObjCompare 缺少返回语句，这就是它隐式返回 undefined 的原因。
• .forEach 方法总是返回undefined，因此您需要将其更改为另一个将返回实际值的方法。我认为 .every 是您在这里所追求的。
• 您不返回递归调用的结果。

总而言之，这会将您的代码段更改为以下内容:

function deepObjCompare(obj1, obj2) {

  return Object.keys(obj1).every((key) => { // Use .every and return the result!
    const key1 = obj1[key];
    const key2 = obj2[key];

    if (key2) {
      if (typeof key1 === "object" && key1 !== null) {
        return deepObjCompare(key1, key2); // Return the result of your recursive call!
      } else if (key1 === key2) {
        return true;
      }
    }
    return false;
  });
}

const obj1 = {
  name: "Bill",
  address: {
    cityNow: "Paris",
    cityFuture: "NYC"
  },
  age: 39
};

const obj2 = {
  name: "Bill",
  address: {
    cityNow: "Paris",
    cityFuture: "NYC"
  },
  age: 39
};

const obj3 = {
  name: "Bob",
  address: "Paris",
  age: 39
};

console.log(deepObjCompare(obj1, obj3)); // false
console.log(deepObjCompare(obj1, obj2)); // true