如何返回对象对象被覆盖的结果

Question

如何返回对象对象被覆盖的结果

我只想返回使用Ecmascript6在firstObject中覆盖firstObject的那些元素

var firstObject = {
  one: 1,
  four: 55,
  six: 6
}

var secondObject = {
  one: 1,
  two: 2,
  three: 3,
  four: 4
}

returnObject = { four:55 }

Answer 1

如果要检查两个对象上都存在哪些属性以及值的差异，可以使用Object.entries将第一个对象转换为数组。使用reduce遍历数组，检查并构造新对象。

var firstObject = {
  one: 1,
  four: 55,
  six: 6
}

var secondObject = {
  one: 1,
  two: 2,
  three: 3,
  four: 4
}

var returnObject = Object.entries(firstObject).reduce((c, [k, v]) => {
  if (secondObject[k] !== undefined && v !== secondObject[k]) c[k] = v;
  return c;
}, {});

console.log(returnObject);

---

一个班轮代码：

var returnObject = Object.entries(firstObject).reduce((c, [k, v]) => secondObject[k] !== undefined && v !== secondObject[k] ? Object.assign(c, {[k]: v}) : c, {})

Answer 2

您可以获取条目，过滤和映射新对象。

var firstObject = { one: 1, four: 55, six: 6 },
    secondObject = { one: 1, two: 2, three: 3, four: 4 }, 
    result = Object.assign({}, ...Object
        .entries(firstObject)
        .filter(([k, v]) => k in secondObject && secondObject[k] !== v)
        .map(([k, v]) => ({ [k]: v }))
    );

console.log(result);