Question

我需要你的帮助...... 我得到了一个像这样的对象数组：

var arr = [{    
  title: 'My title',
  user: 1,
  price: 22,
  location: 'Berlin'
},{    
  title: 'My title',
  user: 1,
  price: 18,
  location: 'Cologne'
},{    
  title: 'My title',
  user: 1,
  price: 26,
  location: 'Hamburg'
},{    
  title: 'Other Title',
  user: 2,
  price: 26,
  location: 'Frankfurt'
},{    
  title: 'Other Title',
  user: 2,
  price: 28,
  location: 'Munich'
},];

现在我想构建一个新的对象数组，如下所示：

var result = [{    
  title: 'My title',
  user: 1,
  events: [
    {
      price: 22,
      location: 'Berlin'
    }, {
      price: 18,
      location: 'Cologne'
    }, {
      price: 26,
      location: 'Hamburg' 
    }
  ]

},{    
  title: 'Other Title',
  user: 2,
  events: [
    {
      price: 28,
      location: 'Munich'
    },{
      price: 26,
      location: 'Frankfurt'
    }
  ]
}];

我需要按多个值对对象进行分组，比如我的示例中的用户和标题，并将它们的唯一数据添加到新字段中。

如果有人能告诉我如何用lodash这样做会很棒！

感谢您的帮助！

Answer 1

    arr.reduce(function (hash, item) {
        var key = item.title + item.user;
        var obj = hash[key] || {};
        obj.title = item.title;
        obj.user = item.user;
        obj.events = obj.events || [];
        obj.events.push({
            price: item.price,
            location: item.location
        });
        hash[key] = obj;
        return hash;
    }, {});

    var result = [];
    for (var key in arr) {
        result.push(arr[key]);
    }

    console.log(result); // the result array

Answer 2

这是一个普通Javascript中的提议，带有一个临时对象，用于引用结果数组。

var arr = [{ title: 'My title', user: 1, price: 22, location: 'Berlin' }, { title: 'My title', user: 1, price: 18, location: 'Cologne' }, { title: 'My title', user: 1, price: 26, location: 'Hamburg' }, { title: 'Other Title', user: 2, price: 26, location: 'Frankfurt' }, { title: 'Other Title', user: 2, price: 28, location: 'Munich' }],
    grouped = function (array) {
        var r = [], o = {};
        array.forEach(function (a) {
            if (!o[a.user]) {
                o[a.user] = { title: a.title, user: a.user, events: [] };
                r.push(o[a.user]);
            }
            o[a.user].events.push({ price: a.price, location: a.location });
        });
        return r;
    }(arr);

document.write('<pre>' + JSON.stringify(grouped, 0, 4) + '</pre>');

Answer 3

Lodash回答：

function remap(arr) {
  var out = _.reduce(arr, function(p, c) {
    var key = [c.user, c.title].join('|');
    p[key] = p[key] || { title: c.title, user: c.user, events: [] };
    p[key].events.push({ price: c.price, location: c.location });
    return p;
  }, {});
  return _.map(_.keys(out), function(el) {
    return out[el];
  });
}

remap(arr);

DEMO

使用包含特定键重复值的对象数组中的唯一数据的数组构建新的对象数组

3 个答案: