仅按关键部分对平面数据库中的键值进行分组

Question

我从平面数据库收到一些数据，如下所示：

[{
        key: "user_15478",
        value: "xxx"
    }, {
        key: "user_name_15478",
        value: "xxx"
    }, {
        key: "user_age_15478",
        value: 5
    }, {
        key: "user_24547",
        value: "xxx"
    }, {
        key: "user_name_24547",
        value: "xxx"
    }, {
        key: "user_age_24547",
        value: 12
    }, {
        key: "user_42412",
        value: "xxx"
    }, {
        key: "user_name_42412",
        value: "xxx"
    }, {
        key: "user_age_42412",
        value: 42
    }
]

什么是更简单的方法，在 vanila js 中或使用像 lodash 这样的库来转换它，按密钥中的数字（15478、24547 等）分组。

例如：

[{
        15478: [{
                key: "user_15478",
                value: "xxx"
            }, {
                key: "user_name_15478",
                value: "xxx"
            }, {
                key: "user_age_15478",
                value: 5
            }
        ]
    }, {
        24547: [{
                key: "user_24547",
                value: "xxx"
            }, {
                key: "user_name_24547",
                value: "xxx"
            }, {
                key: "user_age_24547",
                value: 12
            }
        ]
    }, {
        42412: { {
                key: "user_42412",
                value: "xxx"
            }, {
                key: "user_name_42412",
                value: "xxx"
            }, {
                key: "user_age_42412",
                value: 42
            }
            ]
        }
        ]

提前感谢您的帮助。

Answer 1

这是使用Array.reduce()的解决方案

const transformed = data.reduce((acc, user) => {
    const [ key ] = user.key.match(/\d+$/);
    if (!(key in acc)) {
        acc[+key] = [];
    }
    acc[+key].push(user);
    return acc;
}, {});

给定data 是：

[{
    key: "user_15478",
    value: "xxx"
}, {
    key: "user_name_15478",
    value: "xxx"
}, {
    key: "user_age_15478",
    value: 5
}, {
    key: "user_24547",
    value: "xxx"
}, {
    key: "user_name_24547",
    value: "xxx"
}, {
    key: "user_age_24547",
    value: 12
}, {
    key: "user_42412",
    value: "xxx"
}, {
    key: "user_name_42412",
    value: "xxx"
}, {
    key: "user_age_42412",
    value: 42
}];

Answer 2

如果您的输入数组未排序，那么您首先需要根据key 对其进行排序。 所以排序后会是这样的：

[{key: "user_15478",
 value: "xxx"
 },
{key: "user_24547",
 value: "xxx"
 },
.... //then _age wise
{key: "user_age_42412",
 value: "xxx"
 },
... //then _name wise 
{key: "user_name_42412",
 value: "xxx"
 },
]

然后继续使用 reduce 将对象推送到累加器

let arr= [ { key: "user_15478", value: "xxx" }, { key: "user_name_15478", value: "xxx" }, { key: "user_age_15478", value: 5 }, { key: "user_24547", value: "xxx" }, { key: "user_name_24547", value: "xxx" }, { key: "user_age_24547", value: 12 }, { key: "user_42412", value: "xxx" }, { key: "user_name_42412", value: "xxx" }, { key: "user_age_42412", value: 42 }, ];

arr = arr.sort((a, b) => a.key > b.key ? 1 : -1)

let result=arr.reduce((acc, val) => {
  let field = val.key.split("_")
  if (field.length === 2) {
    acc[field[1]] = [{ ...val
    }]
  }
  else
  acc[field[2]].push(val)
  return acc;
}, {})
let wrappedResult=Object.keys(result).map(key=>({[key]:result[key]}))
console.log(wrappedResult)

Answer 3

您可以使用reduce 和内部回调函数检查使用lastIndexOf 来获取最后一个_。然后检查累加器对象是否存在与数字相同的任何键。如果没有，则创建密钥并为其添加值。

let data = [{
    key: "user_15478",
    value: "xxx"
  },
  {
    key: "user_name_15478",
    value: "xxx"
  },
  {
    key: "user_age_15478",
    value: 5
  },
  {
    key: "user_24547",
    value: "xxx"
  },
  {
    key: "user_name_24547",
    value: "xxx"
  },
  {
    key: "user_age_24547",
    value: 12
  },
  {
    key: "user_42412",
    value: "xxx"
  },
  {
    key: "user_name_42412",
    value: "xxx"
  },
  {
    key: "user_age_42412",
    value: 42
  }
];

let newData = data.reduce((acc, curr) => {
  const _key = curr.key;
  const getNum = _key.substr(_key.lastIndexOf('_') + 1, _key.length);
  if (!acc[getNum]) {
    acc[getNum] = []
  }
  acc[getNum].push(curr)
  return acc;
}, {});
console.log([newData])