javascript - 无法在 Node.js 中使用 MAP 数据结构

Question

我在 Node.js 中的 map 程序中遇到一些问题。我正在尝试在 node.js 程序中使用 MAP，但没有获得值(value)。我已经编写了一些代码来使用 map ，但我认为它不起作用，因为它没有进入循环来获取键值。

请找到以下程序

  async CreateProduceMVPRateAsset(data, callback) {

     var ProducePRICE = {};

             var MVPPRICE =[];
             var MVPPRICE_BS ={};
             var MVPPRICE_LB ={};
             //var ASKINGPRICE= {}// put all the things which need to go to blockchain
            const walletPath = path.join(process.cwd(), 'wallet');
            const wallet = new FileSystemWallet(walletPath);
            console.log(`Wallet path: ${walletPath}`);
            console.log('Data', data);
            console.log('Username', data.username);

 var PRODUCENAME = data.PRODUCE
            console.log('PRODUCENAME', PRODUCENAME);

            var COUNTRY = data.COUNTRY;
            console.log('COUNTRY', COUNTRY);
            var STATE = data.STATE;
            console.log('STATE', STATE);


          var MVPRATES =  data.MVPRATES;  

             console.log('MVPRATERATE', MVPRATES);

             const MVPRATE = new Map(MVPRATES);

// program could not go inside the for loop
             for (const [k, v] of MVPRATE.entries()) {
                 console.log("Inside map", k, v)
                 MVPPRICE = v.RATE  // should go in  MVPPRICE 

                  var Value =  MVPPRICE[0].value // want to get first element value from MVPPRICE array 
                  console.log('Value', Value);

                 var value_lb = Value/40;
                 console.log('value_lb', value_lb);

                 value_lb = Number((value_lb).toFixed(4));

                    console.log('If the value of BS provided controller come here');

                    MVPPRICE_LB.Value = value_lb
                    MVPPRICE_LB.QuantityUnit = 'LB'
                    MVPPRICE_LB.uidisplay = false
                    MVPPRICE_LB.CurrencyUnit = 'USD'

                    MVPPRICE.push(MVPPRICE_LB);
                    ProducePRICE.MVPPRICE = MVPPRICE

                        console.log('MVPPRICE',MVPPRICE);
                   console.log('ProducePRICE',ProducePRICE);

                    // mvpprice.totalPrice = totalPrice;
                    console.log('for pricing',totalPrice);

                    // ProducePRICE.VARIETY = VARIETY;
                    ProducePRICE.PRODUCENAME = PRODUCENAME;
                    ProducePRICE.STATE = STATE;
                    ProducePRICE.COUNTRY = COUNTRY;

              }

我使用 postman 发送的 JSON 结构

{
"username": "admin2",
  "PRODUCE": "Apple",
  "STATE": "MI",
  "COUNTRY": "US",
  "MVPRATES": {
    "fuji": {
      "VARIETY": "fuji",
      "RATE": [
        {
          "UNIT": "Bussel",
          "CURRENCY": "USD",
          "VALUE": 10.25,
          "UIDISPLAY": true
        }
      ]
    },
    "gala": {
      "VARIETY": "gala",
      "RATE": [
        {
          "UNIT": "Bussel",
          "CURRENCY": "USD",
          "VALUE": 10.25,
          "UIDISPLAY": true
        }
      ]
    }
  }
}

我得到的输出:

Answer 1

似乎您可能想要执行以下操作，这将创建一个包含两个条目的 Map:fuji 和 gala

const MVPRATES = {
  "fuji": {
    "VARIETY": "fuji",
    "RATE": [{
      "UNIT": "Bussel",
      "CURRENCY": "USD",
      "VALUE": 10.25,
      "UIDISPLAY": true
    }]
  },
  "gala": {
    "VARIETY": "gala",
    "RATE": [{
      "UNIT": "Bussel",
      "CURRENCY": "USD",
      "VALUE": 10.25,
      "UIDISPLAY": true
    }]
  }
}
const MVPRATE = new Map(Object.entries(MVPRATES));
for (const [k, v] of MVPRATE.entries()) {
  console.log("Inside map", k, v)
}

尽管如此，对 Map 的需求仍不清楚，因为您可以通过以下方式实现上述目标

const MVPRATES = {
  "fuji": {
    "VARIETY": "fuji",
    "RATE": [{
      "UNIT": "Bussel",
      "CURRENCY": "USD",
      "VALUE": 10.25,
      "UIDISPLAY": true
    }]
  },
  "gala": {
    "VARIETY": "gala",
    "RATE": [{
      "UNIT": "Bussel",
      "CURRENCY": "USD",
      "VALUE": 10.25,
      "UIDISPLAY": true
    }]
  }
}
for (const [k, v] of Object.entries(MVPRATES)) {
  console.log("Inside map", k, v)
}