使用下划线获取所有键和每个键的唯一值列表

Question

从一组对象开始，我需要获取所有键的列表以及每个键的所有唯一值。问题是我事先不知道钥匙。如果您知道密钥，则有很多解决方案，但在这种情况下，每个对象都可以有任意数量的密钥，并且每个密钥都有一个值数组。下面的代码可以工作，但是它很复杂，必须有一个更简单的解决方案。

Made a working JSBIN here

输入：

[
    {
        key_1: [ attribute_value_1, attribute_value_2, ... ],
        key_2: [ attribute_value_3, attribute_value_4, ... ],
    },
    ...
]

输出：

[
    {
        label: key_1,
        options: [ attribute_value_1, attribute_value_2, ... ]
    },
    {
        label: key_2,
        options: [ attribute_value_3, attribute_value_4, ... ]
    },
    ...
]

建议的解决方案：

    _.chain(input)
        .map(function (attr) {
            return _.keys(attr).map(function (key) {
                return {
                    key: key,
                    value: attr[key]
                };
            });
        })
        .flatten()
        .groupBy('key')
        .map(function (grouped_values, key) {
            // value = array of { key, value }
            return {
                label: key,
                options: _.chain(grouped_values)
                    .pluck('value')
                    .flatten()
                    .uniq()
                    .value()
            };
        })
        .value();

Answer 1

使用 lodash - 将结果应用 _.mergeWith() to the input array, and use the customizer function to combine the arrays and get the unique values. Afterwards _.map() 为所需格式：

var input = [
  {
    key_1: [ "attribute_value_1", "attribute_value_2" ],
    key_2: [ "attribute_value_3", "attribute_value_4" ]
  },
  {
    key_1: [ "attribute_value_1", "attribute_value_5" ],
    key_2: [ "attribute_value_2", "attribute_value_3" ],
    key_5: [ "attribute_value_2", "attribute_value_3" ]
  }
];


var params = [{}].concat(input).concat(function (objValue, srcValue) { // create the params to apply to mergeWith
  if (_.isArray(objValue)) {
    return _.union(objValue, srcValue); // merge the arrays, and get the unique values
  }
});

var result = _.map(_.mergeWith.apply(_, params), function(value, key) { // merge all objects in the array, and map the results to required format
  return {
    label: key,
    options: value
    };
  });

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.16.2/lodash.min.js"></script>

如果你使用 ES6，你可以清理丑陋的 params 数组：

const input = [
  {
    key_1: [ "attribute_value_1", "attribute_value_2" ],
    key_2: [ "attribute_value_3", "attribute_value_4" ]
  },
  {
    key_1: [ "attribute_value_1", "attribute_value_5" ],
    key_2: [ "attribute_value_2", "attribute_value_3" ],
    key_5: [ "attribute_value_2", "attribute_value_3" ]
  }
];

const customizer = (objValue, srcValue) => {
  if (_.isArray(objValue)) {
    return _.union(objValue, srcValue); // merge the arrays, and get the unique values
  }
};

const result = _.map(_.mergeWith({}, ...input, customizer), (value, key) => ({ // merge all objects in the array, and map the results to required format
  label: key,
  options: value
}));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.16.2/lodash.min.js"></script>

Answer 2

如果你愿意，你可以用 Underscore 写这个，但没有迫切需要这样做。

const input = [
  {key_1: [1, 2], key_2: [3, 4]},
  {key_3: [5, 6], key_2: [7, 42]}
 ];

var result = [].concat(...input.map(obj => 
  Object.keys(obj).map(key =>
    ({label: key, options: obj[key]})
  )
));

console.log(result);

我不太确定你想如何统一结果。你的意思是你想在每个数组中运行唯一，例如 [ attribute_value_1, attribute_value_2, ... ]?

使用下划线获取所有键和每个键的唯一值列表

Using underscore to get all keys and list of unique values for each

javascript

arrays

functional-programming

underscore.js

lodash