如何检查在另一个对象中找到的对象的已知索引的值是否存在

Question

假设我有以下对象

var myObject = {
 index1: {
    indexsub1: index1value1,
    indexsub2: index1value2,
 },
 index2: {
    indexsub1: index2value1,
    indexsub2: index2value2,
 },
 index3: {
    indexsub1: index3value1,
    indexsub2: index3value2,
 },
}

如何在不知道index1，index2和index3的情况下检查myObject中是否存在值为x的indexsub1。

Answer 1

var myObject = {
 index1: {
    indexsub1: 1,
    indexsub2: 2,
 },
 index2: {
    indexsub1: 3,
    indexsub2: 4,
 },
 index3: {
    indexsub1: 5,
    indexsub2: 6,
 },
}

// key exists and value equal
console.log(
  Object.keys(myObject).some(key => myObject[key]['indexsub1'] === 1)
);

// key exists but value not equal
console.log(
  Object.keys(myObject).some(key => myObject[key]['indexsub1'] === 7)
);

// key doesn't exist
console.log(
  Object.keys(myObject).some(key => myObject[key]['indexsub7'] === 7)
);

Answer 2

var myObject = {
  index1: {
    indexsub1: 1,
    indexsub2: 2,
  },
  index2: {
    indexsub1: 3,
    indexsub2: 4,
  },
  index3: {
    indexsub1: 5,
    indexsub2: 6,
  },
};

function hasKeyValue(key, value) {
  for (var prop in myObject) {
    if (myObject[prop][key] === value)
      return true;
  }
  return false;
}

console.log(hasKeyValue("indexsub1", 5));
console.log(hasKeyValue("indexsub1", 7));

Answer 3

使用Object.keys()，您可以获取对象的所有键。这将生成一个数组['index1', 'index2', 'index3']。

Object.keys(myObject)

现在您可以使用它来访问所有子对象，并检查属性indexsub1是否具有特定值：

const hasX = Object.keys(myObject).any(index => {
  const subObject = myObject[index];
  if (subObject.indexsub1 == 'x') {
    return true;
  } else {
    return false;
  }
});