方式一：手动比较

• 代码示例

  function isObjectValueEqual(a, b) {
      // 获取对象 a 和 b 的属性名
      var aProps = Object.getOwnPropertyNames(a);
      var bProps = Object.getOwnPropertyNames(b);
      // 判断属性名的数量是否一致
      if (aProps.length != bProps.length) {
          return false;
      }
      // 循环取出属性名，再判断属性值是否一致
      for (var i = 0; i < aProps.length; i++) {
          var propName = aProps[i];
          if (a[propName] !== b[propName]) {
              return false;
          }
      }
      return true;
  }

• 使用示例

  var obj1 = { name: "Benjamin", sex: "male" };
  var obj2 = { name: "Benjamin", sex: "male" };
  var obj3 = { name: "John", sex: "male" };
  console.log(isObjectValueEqual(obj1, obj2)); // true
  console.log(isObjectValueEqual(obj1, obj3)); // false

方式二：浅层比较

• 定义：浅层比较是指只比较对象的第一层属性值，而不深入比较嵌套的对象

• 代码示例

  function shallowEqual(object1, object2) {
      const keys1 = Object.keys(object1);
      const keys2 = Object.keys(object2);
      if (keys1.length !== keys2.length) {
          return false;
      }
      for (let index = 0; index < keys1.length; index++) {
          const val1 = object1[keys1[index]];
          const val2 = object2[keys2[index]];
          if (val1 !== val2) {
              return false;
          }
      }
      return true;
  }

• 使用示例

  const hero1 = { name: 'Batman', realName: 'Bruce Wayne' };
  const hero2 = { name: 'Batman', realName: 'Bruce Wayne' };
  const hero3 = { name: 'Joker' };
  console.log(shallowEqual(hero1, hero2)); // true
  console.log(shallowEqual(hero1, hero3)); // false

方式三：深层比较

• 定义：深层比较不仅比较对象的第一层属性值，还会递归比较嵌套的对象，使用递归函数实现

• 代码示例

  function deepEqual(object1, object2) {
      const keys1 = Object.keys(object1);
      const keys2 = Object.keys(object2);
      if (keys1.length !== keys2.length) {
          return false;
      }
      for (let index = 0; index < keys1.length; index++) {
          const val1 = object1[keys1[index]];
          const val2 = object2[keys2[index]];
          const areObjects = isObject(val1) && isObject(val2);
          if (areObjects && !deepEqual(val1, val2) || !areObjects && val1 !== val2) {
              return false;
          }
      }
      return true;
  }
  function isObject(object) {
      return object != null && typeof object === 'object';
  }

• 使用示例

  const hero1 = { name: 'Batman', address: { city: 'Gotham' } };
  const hero2 = { name: 'Batman', address: { city: 'Gotham' } };
  console.log(deepEqual(hero1, hero2)); // true