Angular 为数组中的每个日期添加一次Typescript（多个日期）

我有一个包含几个字段的对象数组。看起来是这样的：

[
    {"date": "01/01/2020", "location": "Main St", "customers": 100, "shoppers": 150, "visitors": 2000},
    {"date": "01/01/2020", "location": "Lower St", "customers": 105, "shoppers": 166, "visitors": 2000},
    {"date": "01/01/2020", "location": "High St", "customers": 180, "shoppers": 260, "visitors": 2000},
    {"date": "02/01/2020", "location": "Main St", "customers": 156, "shoppers": 194, "visitors": 1566},
    {"date": "02/01/2020", "location": "Lower St", "customers": 80, "shoppers": 201, "visitors": 1566},
    {"date": "02/01/2020", "location": "High St", "customers": 97, "shoppers": 133, "visitors": 1566},
    {"date": "03/01/2020", "location": "Main St", "customers": 48, "shoppers": 97, "visitors": 1002},
    {"date": "03/01/2020", "location": "Lower St", "customers": 211, "shoppers": 287, "visitors": 1002},
    {"date": "03/01/2020", "location": "High St", "customers": 113, "shoppers": 233, "visitors": 1002}
]

如您所见，每天的访客数量是固定的（因为它已经是当天的总访客）

我将客户和购物者汇总如下：

this.customerCount = this.data.filter(item => item.date >= this.startDate && item.date <= this.endDate)
      .reduce((sum, current) => sum + current.customers, 0);

this.shopperCount = this.data.filter(item => item.date >= this.startDate && item.date <= this.endDate)
      .reduce((sum, current) => sum + current.shoppers, 0);

---

您应该做的第一件事是修复数据比较，我认为这种日期比较在所有情况下都不起作用，要么将日期格式转换为

yyy-mm-dd

或日期对象，然后进行日期比较

修复后，您可以使用Array.reduce通过以下方式获得访客总数：

const sum = this.data.reduce((acc, item) => 
    {
        if (item.date >= this.startDate && item.date <= this.endDate) {
            if (!acc.map[item.date.toString()]) {
                acc.map[item.date.toString()] = true;
                acc.sum += item.visitors;
            }
        }
        return acc;
    }, {map: {}, sum: 0}).sum;

const sum=this.data.reduce（（acc，item）=>
{
如果（item.date>=this.startDate&&item.date，item.data指的是什么？@nimgwfc这是一个打字错误，“data”代替了“date”，很久以前就编辑过。这就是我的想法，谢谢！尽管我收到一个错误，item.date不能用作索引类型，因为它是Date@nimgwfc这是一个typescript警告，看起来你的日期无论如何都是字符串，但无论如何，上面的编辑应该会使警告消失。
const sum = this.data.reduce((acc, item) => 
    {
        if (item.date >= this.startDate && item.date <= this.endDate) {
            if (!acc.map[item.date.toString()]) {
                acc.map[item.date.toString()] = true;
                acc.sum += item.visitors;
            }
        }
        return acc;
    }, {map: {}, sum: 0}).sum;