javascript - 按日期对数组中的项目进行分组

Question

我有一个包含日期和容器颜色的数组。有些垃圾箱是在同一日期收集的，所以我想对这些日期进行分组，然后得到一系列垃圾箱颜色。

我想要实现的数据结构是:

"items": [
        "item": {
            "date": "2019-10-18T00:00:00.000Z",
            "bins": [{
                "bin": "Blue"
            }, {
                "bin": "Grey"
            }]
        },
        ...
]

数据数组:

var dateList = [{
        "date": "2019-10-18T00:00:00.000Z",
        "bin": "Blue"
    }, {
        "date": "2019-11-08T00:00:00.000Z",
        "bin": "Blue"
    }, {
        "date": "2019-11-01T00:00:00.000Z",
        "bin": "Green"
    }, {
        "date": "2019-11-22T00:00:00.000Z",
        "bin": "Green"
    }, {
        "date": "2019-10-18T00:00:00.000Z",
        "bin": "Grey"
    }, {
        "date": "2019-11-01T00:00:00.000Z",
        "bin": "Grey"
    }]

这是我到目前为止的代码，它几乎就在那里，但不是创建 items.item，而是创建 items[date]，但我无法弄清楚最后一部分:

    var items = {};
    for(var i = 0; i < dateList.length; i++) {

        if(!items[dateList[i].date]) {

            items[dateList[i].date] = {};
            items[dateList[i].date].date = dateList[i].date;
            items[dateList[i].date].bins = [];
            items[dateList[i].date].bins.push( { "bin": dateList[i].bin });

        } else {
            items[dateList[i].date].bins.push( { "bin": dateList[i].bin }); 
        }
    } 

这会产生项目[日期]

"items": {
    "2019-10-18T00:00:00.000Z": {
        "date": "2019-10-18T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }, {
            "bin": "Grey"
        }]
    },
    "2019-11-08T00:00:00.000Z": {
        "date": "2019-11-08T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }]
    },
    "2019-11-01T00:00:00.000Z": {
        "date": "2019-11-01T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }, {
            "bin": "Grey"
        }]
    },
    "2019-11-22T00:00:00.000Z": {
        "date": "2019-11-22T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }]
    }
}

如果我能像 items.item 那样构造它，我会更喜欢它

"items": [
    "item": {
        "date": "2019-10-18T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }, {
            "bin": "Grey"
        }]
    },
    "item": {
        "date": "2019-11-08T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }]
    },
    "item": {
        "date": "2019-11-01T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }, {
            "bin": "Grey"
        }]
    },
    "item": {
        "date": "2019-11-22T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }]
    }
]

谢谢

Answer 1

要获取对象数组，可以使用以下代码。请注意，使用 Object.keys() 时的顺序无法保证。

我放了两种方法，一种是简单的数组，第二种是用 item 关键字作为数组中每个对象的包装器的数组。

const items = {
    "2019-10-18T00:00:00.000Z": {
        "date": "2019-10-18T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }, {
            "bin": "Grey"
        }]
    },
    "2019-11-08T00:00:00.000Z": {
        "date": "2019-11-08T00:00:00.000Z",
        "bins": [{
            "bin": "Blue"
        }]
    },
    "2019-11-01T00:00:00.000Z": {
        "date": "2019-11-01T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }, {
            "bin": "Grey"
        }]
    },
    "2019-11-22T00:00:00.000Z": {
        "date": "2019-11-22T00:00:00.000Z",
        "bins": [{
            "bin": "Green"
        }]
    }
}

const array = Object.keys(items).map(key => items[key]);
const arrayWithItems = Object.keys(items).map(key => ({item: items[key]}));
console.log(array);
console.log('!!!! -------- !!!!!');
console.log(arrayWithItems);