node.js - TypeError：无法读取未定义的属性“DASH”

Question

在我当前的项目中，我想显示一些数据（加密统计）。通过调用 API，我得到了有效的响应。

我的环境是：

节点：8.9.5，Express：4.16.4，Angular CLI：7.3.6，Typescript：3.2.4，操作系统：darwin x64

这是我的代码：

const express = require('express')
const bodyParser = require('body-parser')
const request = require('request')
const cors = require('cors')

// Create an express app
const app = express()

// Error-fix: Cross-Origin
app.use(cors())

ticker = "DASH";

// Define a default route handler for the Node app
app.get('/getDetails', (req, res) => {
    let options = {
        'url': 'https://api-call-something.io/',
        'formData': {"access-token": "xxxxx-xxxxx-xxxxx", "ticker": ticker},
        'method': "POST"
    }; 

    request(options).pipe(res);
})

这是我的回应：

回复：

{
    "success": true,
    "message": {
        "DASH": {
            "semantic_version": "0.12.3.3",
            "last_block": 982197,
            "block_age": 446554,
            "statuses": {
                "ENABLED": 4898,
                "SENTINEL_PING_EXPIRED": 11,
                "NEW_START_REQUIRED": 46,
                "UPDATE_REQUIRED": 60,
                "PRE_ENABLED": 1,
                "POSE_BAN": 1
            },
            "usd_price": 111.50325810328,
            "btc_price": "0.02107716",
            "change_24h": -2.42056,
            "roi": 6.77475551,
            "collateral": 1000,
            "payout_sum_daily": "909.11649250",
            "payout_count_daily": 543,
            "payout_period": 779350.464,
            "daily_income": {
                "coin": 0.1856,
                "btc": "0.00391213",
                "usd": 20.6961
            }
        }
    }
}

当我尝试访问 usd_price 值时，出现错误：

app.get('/getDetails', (req, res) => {
    let options = {
        'url': 'https://api-call-something.io/',
        'formData': {"access-token": "xxxxx-xxxxx-xxxxx", "ticker": ticker},
        'method': "POST"
    };

    request(options).pipe(res);

    usd = res.message['DASH'].usd_price;

    console.log(usd);
    console.log(res);
})

TypeError: Cannot read property 'DASH' of undefined

标签： node.jsangularapiexpress

Answer 1

使用此方法：

    let message = res['message'];
    let dash = Object.keys(message)[0];
    let jsonObject: any = message[dash];
    console.log("USD Price: " + jsonObject['usd_price']);