按属性排序对象javascript数组

Question

我有一个未排序的对象数组，它具有两个相关属性：type和date。我需要对这个数组进行排序：

1. 按日期和
2. 按类型(每年，deposit应优先于withdrawal)

下面是一个输入示例：

let i = [
    {
        date:'2017',
        type:'withdrawal',
        amount:-5
    },
    {
        date:'2016',
        type:'deposit',
        amount:12
    },
    {
        date:'2018',
        type:'deposit',
        amount:54
    },
    {
        date:'2017',
        type:'deposit',
        amount:20
    },
    {
        date:'2016',
        type:'withdrawal',
        amount:55
    },
    {
        date:'2018',
        type:'withdrawal',
        amount:54
    }
]  

目标是输出类似这样的内容：

let o = [
    {
        date:'2016',
        type:'deposit',
        amount:12
    },
    {
        date:'2016',
        type:'withdrawal',
        amount:55
    },
    {
        date:'2017',
        type:'deposit',
        amount:20
    },
    {
        date:'2017',
        type:'withdrawal',
        amount:-5
    },
    {
        date:'2018',
        type:'deposit',
        amount:54
    },
    {
        date:'2018',
        type:'withdrawal',
        amount:54
    }
]

到目前为止，我使用以下方法按日期对数组进行排序：

o = i.sort((a,b)=>(a.date - b.date))

但我找不到一种按类型分类的方法

Answer 1

你可以像下面这样使用“排序”。通过使用"localeCompare“，它将按递增的顺序对”类型“进行排序，即”存款“在”取款“之前，而"d”则在"w“之前。

就是用这个-

i.sort((a,b) => ((+a.date) - (+b.date) || (a.type.localeCompare(b.type))))

• 首先按“日期”排序，如果日期相同，则在OR条件下( a.date - b.date将为0)检查“类型”。

​

let i = [
    {
        date:'2017',
        type:'withdrawal',
        amount:-5
    },
    {
        date:'2016',
        type:'deposit',
        amount:12
    },
    {
        date:'2018',
        type:'deposit',
        amount:54
    },
    {
        date:'2017',
        type:'deposit',
        amount:20
    },
    {
        date:'2016',
        type:'withdrawal',
        amount:55
    },
    {
        date:'2018',
        type:'withdrawal',
        amount:54
    }
]  

i.sort((a,b) => ((+a.date) - (+b.date) || (a.type.localeCompare(b.type))))

console.log(i)

​

Answer 2

可以使用string#localCompare对数组进行排序，首先是基于date，然后是基于type。

​

let arr = [ { date:'2017', type:'withdrawal', amount:-5 }, { date:'2016', type:'deposit', amount:12 }, { date:'2018', type:'deposit', amount:54 }, { date:'2017', type:'deposit', amount:20 }, { date:'2016', type:'withdrawal', amount:55 }, { date:'2018',type:'withdrawal', amount:54 } ];
arr.sort((a,b) => a.date.localeCompare(b.date) || a.type.localeCompare(b.type));
console.log(arr);

​

Answer 3

虽然可能不是最理想的解决方案，但我将类型作为Array.prototype.sort方法中"a“和"b”的字符串连接到date上，并根据该字符串对数组进行排序。

i.sort((a,b) => {
  let aStr = `${a.date}${a.type}`;
  let bStr = `${b.date}${b.type}`;
  if(aStr > bStr) {
    return 1;
  } else if(aStr === bStr) {
    return 0;
  } else {
    return -1;
  }
});

希望这能帮上忙！