在子对象数组中搜索- JavaScript

Question

目前，我有以下的数组对象

obj = [
    {
        "id":28,
        cities: [
            {
                cityTypes: "AA",
                citySource: "sdsf"
            },
            {
                cityTypes: "BB",
                citySource: "sdsgf"
            },
            {
                cityTypes: "CC",
                citySource: "fgsdfgd"
            }
        ]
    }, 
    {
        "id":56,
        cities: [
            {
                cityTypes: "DD",
                citySource: "sdsf"
            },
            {
                cityTypes: "EE",
                citySource: "sdsgf"
            },
            {
                cityTypes: "FF",
                citySource: "fgsdfgd"
            }
        ]
    }, 
    {
        "id":89,
        cities: [
            {
                cityTypes: "GG",
                citySource: "sdsf"
            },
            {
                cityTypes: "HH",
                citySource: "sdsgf"
            },
            {
                cityTypes: "II",
                citySource: "fgsdfgd"
            }
        ]
    }
]

我需要搜索特定值的cityTypes在整个Object中。

假设，我需要搜索cityTypes = BB

如果整个对象中存在BB，则返回true

如果BB未预置，则返回false。

这就是我尝试过的，但似乎行不通。

for(let k=0; k<obj.length; k++){
    if(obj[k].cities){
        let cityObj = obj[k].cities;
        for(let city in cityObj){
            city.cityTypes !== "BB" ? "true" : "false"
        }
    }
}

什么是正确的方法来实现这一点？

Answer 1

您可以在另一个.some中使用.some

​

const obj=[{"id":28,cities:[{cityTypes:"AA",citySource:"sdsf"},{cityTypes:"BB",citySource:"sdsgf"},{cityTypes:"CC",citySource:"fgsdfgd"}]},{"id":56,cities:[{cityTypes:"DD",citySource:"sdsf"},{cityTypes:"EE",citySource:"sdsgf"},{cityTypes:"FF",citySource:"fgsdfgd"}]},{"id":89,cities:[{cityTypes:"GG",citySource:"sdsf"},{cityTypes:"HH",citySource:"sdsgf"},{cityTypes:"II",citySource:"fgsdfgd"}]}];

console.log(
  obj.some(({ cities }) => cities.some(({ cityTypes }) => cityTypes === 'BB'))
);
console.log(
  obj.some(({ cities }) => cities.some(({ cityTypes }) => cityTypes === 'foobar'))
);

​

Answer 2

由于以下几个原因，现有代码无法工作：

1. 您需要执行let city of cityObj，因为您在内部循环中以city.cityTypes的形式访问city的属性，因此使用of将给出city变量中的每个对象。
2. 您需要实际检查是否找到匹配，是否使用if条件。如果在您期望的cityTypes中找到匹配，那么break内部循环。如果找到匹配，也可以使用break外部循环。

​

var obj = [{
    "id": 28,
    cities: [{
        cityTypes: "AA",
        citySource: "sdsf"
      },
      {
        cityTypes: "BB",
        citySource: "sdsgf"
      },
      {
        cityTypes: "CC",
        citySource: "fgsdfgd"
      }
    ]
  },
  {
    "id": 56,
    cities: [{
        cityTypes: "DD",
        citySource: "sdsf"
      },
      {
        cityTypes: "EE",
        citySource: "sdsgf"
      },
      {
        cityTypes: "FF",
        citySource: "fgsdfgd"
      }
    ]
  },
  {
    "id": 89,
    cities: [{
        cityTypes: "GG",
        citySource: "sdsf"
      },
      {
        cityTypes: "HH",
        citySource: "sdsgf"
      },
      {
        cityTypes: "II",
        citySource: "fgsdfgd"
      }
    ]
  }
]
var found = false;
for (let k = 0; k < obj.length; k++) {
  if (obj[k].cities) {
    let cityObj = obj[k].cities;
    for (let city of cityObj) {
      found = city.cityTypes === "BB";
      if (found) {
        break;
      }
    }
  }
  if (found) {
    break;
  }
}
console.log(found);

​

Answer 3

使用双减缩应该有效

​

var obj = [{
    "id": 28,
    cities: [{
        cityTypes: "AA",
        citySource: "sdsf"
      },
      {
        cityTypes: "BB",
        citySource: "sdsgf"
      },
      {
        cityTypes: "CC",
        citySource: "fgsdfgd"
      }
    ]
  },
  {
    "id": 56,
    cities: [{
        cityTypes: "DD",
        citySource: "sdsf"
      },
      {
        cityTypes: "EE",
        citySource: "sdsgf"
      },
      {
        cityTypes: "FF",
        citySource: "fgsdfgd"
      }
    ]
  },
  {
    "id": 89,
    cities: [{
        cityTypes: "GG",
        citySource: "sdsf"
      },
      {
        cityTypes: "HH",
        citySource: "sdsgf"
      },
      {
        cityTypes: "II",
        citySource: "fgsdfgd"
      }
    ]
  }
]
var cityTypes1 = 'BB';
console.log(obj.reduce((total, cur) => 
    total||cur.cities.reduce((total, cur) => 
        total||cur.cityTypes === cityTypes1, false), 
    false))

​