javascript - JavaScript中如何基于key从数组中过滤？

Question

我正在收到所有工作订单的回复。

{
  "jobOrders": [{
      "id": "5b4f7ad860dfee3b009d7452",
      "haulier": {
        "companyName": "BigDataMatica",
        "email": "nirmalkumar.s@datinfi.com",
        "registrationNumber": "nirmal89HJ",
        "companyAddress": "RSPURAM",
        "companyPhone": "8687678",
        "yardAddress": "Pragatinagar",
        "yardPhone": "69876876",
        "haulierCode": "Haulier",
        "billingAddress": "Pragatinagar"
      }
    },
    {
      "id": "5b501f8f60dfee3b009d7454",
      "haulier": {
        "companyName": "BigDataMatica",
        "email": "nirmalkumar.s@datinfi.com",
        "registrationNumber": "nirmal89HJ",
        "companyAddress": "RS PURAM",
        "companyPhone": "8687678",
        "yardAddress": "Pragatinagar",
        "yardPhone": "69876876",
        "haulierCode": "Haulier",
        "billingAddress": "Pragatinagar"
      }
    },
    {
      "id": "5b5020f360dfee3b009d7455",
      "haulier": {
        "companyName": "BigDataMatica",
        "email": "sivasai.s@datinfi.com",
        "registrationNumber": "nirmal89HJ",
        "companyAddress": "RS PURAM",
        "companyPhone": "8687678",
        "yardAddress": "Pragatinagar",
        "yardPhone": "69876876",
        "haulierCode": "Haulier",
        "billingAddress": "Pragatinagar"
      }
    }
  ]
}

根据作业订单，我需要根据haulier对象email键过滤作业订单。

let haulierjobordersnames = joborderlist && joborderlist.map && joborderlist.map(a => a.haulier.email);
console.log("haulierjobordersnames", haulierjobordersnames);

输出:

["nirmalkumar.s@datinfi.com", "nirmalkumar.s@datinfi.com", "sivasai.s@datinfi.com"]

<小时/>

let haulierjoborders = joborderlist && joborderlist.map && joborderlist.map((el)=>{el.haulier.email == haulierjobordersnames})
console.log("haulierjoborders", haulierjoborders);

输出:

[undefined, undefined, undefined]

Answer 1

两个问题:

1. 如果需要过滤，需要调用.filter，而不是(仅).map
2. 如果您在回调函数中使用大括号，它将被视为代码块，因此您需要返回一些内容。否则跳过大括号，以便使用表达式语法。

所以:

joborderlist.map((el)=>{el.haulier.email == haulierjobordersnames})

应该变成:

joborderlist.filter((el)=>el.haulier.email == haulierjobordersnames)
            .map((el) => el.haulier.email)

显然，通过这种方式，输出将重复相同的值，因此您可能想提取除刚刚过滤的电子邮件之外的其他信息。