如何遍历对象的属性值以验证某些值（也包括对象）的其他特定属性值？

Question

所以我试图遍历一个对象以查看它是否具有特定的“id”键。我试过hasOwnProperty()、.includes 和“if 'id' in item”。我也刚刚尝试检查对象的实际长度，但仍然无法正常工作。我不知道为什么这些选项都不起作用。

在这张图片中，我尝试计算flightsbyId 对象中的键数。它所做的只是返回项目中的字符数，而不是父对象中的对象数。

看看控制台。它对所有对象都表示错误，但是除了一个之外，所有对象都有一个 id 键。

Ex 对象：

const formik = {
  randomObj: "something",
  values: {
    flight1: { name: "flight1", timecreated: "sometime", id: 548497984 },
    flight2: { name: "flight2", timecreated: "sometime", id: 548497982 },
    flight3: { name: "flight3", timecreated: "sometime", id: 548497989 },
    flight4: { name: "flight4", timecreated: "sometime", id: 548497981 },
  },
  attributes: null,
};

我期望写成伪代码：

if 'id' in flight1, console.log(true), else console.log(false)

或

if length(flight1)=== a number, return true

这有意义吗？

Answer 1

这是查找特定 ID 的一种方法。我安慰找到的物体和那个特定物体的长度。但我不清楚你到底想要什么。

let formik = {
  "randomObj": 'something',
  "values": {
    flight1: {
      'name': "flight1",
      'timecreated': "sometime",
      id: 548497984
    },
    flight2: {
      'name': "flight2",
      'timecreated': "sometime",
      id: 548497982
    },
    flight3: {
      'name': "flight3",
      'timecreated': "sometime",
      id: 548497989
    },
    flight4: {
      'name': "flight4",
      'timecreated': "sometime",
      id: 548497981
    }
  },
  attributes: 'null'
}

for (let key in formik.values) {
  if (formik.values[key].id === 548497984) {
    console.log(formik.values[key])
    console.log("Length is: ", Object.keys(formik.values[key]).length)
    break;
  } else {
    console.log("no matches")
  }
}

Answer 2

every 和 some 是在操作数据项列表时获取布尔结果/答案的首选方法。

另外应该提到的是，这两种方法都会提前退出数组的迭代，这意味着只要every 条件失败或some 条件匹配。

const formik = {
  randomObj: "something",
  values: {
    flight1: { name: "flight1", timecreated: "sometime", id: 548497984 },
    flight2: { name: "flight2", timecreated: "sometime", id: 548497982 },
    flight3: { name: "flight3", timecreated: "sometime", id: 548497989 },
    flight4: { name: "flight4", timecreated: "sometime", id: 548497981 },
  },
  attributes: null,
};

console.log(
  '... does flight with `id: 548497989` exist ?..',
  Object
    .values(formik.values)
    .some(({ id }) => id === 548497989)
)
console.log(
  '... does flight with `id: 123456789` exist ?..',
  Object
    .values(formik.values)
    .some(({ id }) => id === 123456789)
)

.as-console-wrapper { min-height: 100%!important; top: 0; }

如果 OP 想要通过其 id 来 find 一个 flight 项目，那么上面提供的代码只需要通过其方法名称进行更改。

因此some和find之间的唯一区别是前者的返回值true/false和后者的undefined值或匹配的数组项。

const formik = {
  randomObj: "something",
  values: {
    flight1: { name: "flight1", timecreated: "sometime", id: 548497984 },
    flight2: { name: "flight2", timecreated: "sometime", id: 548497982 },
    flight3: { name: "flight3", timecreated: "sometime", id: 548497989 },
    flight4: { name: "flight4", timecreated: "sometime", id: 548497981 },
  },
  attributes: null,
};

console.log(
  '... find flight with `id: 548497989` ...',
  Object
    .values(formik.values)
    .find(({ id }) => id === 548497989)
);
console.log(
  '... find flight with `id: 123456789` ...',
  Object
    .values(formik.values)
    .find(({ id }) => id === 123456789)
);

console.log(
  '... how many properties has flight with `id: 548497989` ?..',
  Object.keys(

    Object
    .values(formik.values)
    .find(({ id }) => id === 548497989) ?? {}

  ).length || null // || -1 // || 'none'
);
console.log(
  '... how many properties has flight with `id: 123456789` ?..',
  Object.keys(

    Object
    .values(formik.values)
    .find(({ id }) => id === 123456789) ?? {}

  ).length || null // || -1 // || 'none'
);

.as-console-wrapper { min-height: 100%!important; top: 0; }

Answer 3

const idsOrLength = Object.keys(formik.values.flightsById).map(({ itemKey }) => {
      const item = formik.values.flightsById[itemKey];
      const { id } = item;
      const length = Object.keys(item).length

      return id || length;
});