NodeJS-在函数中调用Fetch会挂起控制台

我在React客户端遇到了一个问题,所以我使用了一个更简单的单文件节点程序来重现这个错误。在react客户端中,我没有得到任何数据。通过使用Postman,我能够执行“获取”并检索JSON数据。

有人能帮我把这个挂起来吗?

我最近在服务器端gettranslations中做了一个类似的函数,这样我就可以从一个函数调用MongoDB。( NodeJS ASync call of MongoClient GetData routine )1.我想我的回答是一样的。

我曾考虑过使用“wait”,但我不使用异步函数。在我刚才提到的上述示例中,我不需要“wait”,因为函数使用“wait”。然后是“模式”。

部分代码:

const fetch = require("node-fetch");

function getDBLanguagesAndConvertToDataTable(fromLanguage, toLanguage) { 
  // TODO implement from/to Language in URL below  
  console.log("Function: " + getFormattedTime())
  return fetch('http://localhost:3001/api/gettranslations/en-US/es-MX', {
                  method: 'GET',
                  headers: {
                    'Accept': 'application/json'
                  }
    })
  .then(function(data) {
     // do something with the data 
     console.log("Status:", data.status)
     console.log("data from DB:")
     console.log(JSON.stringify(data)) 
     console.log("data.body:")
     console.log(JSON.stringify(data.json())) 
     // I call another function here to reshape the data, 
     // but even with that commented out, same issue. 
     return data.json() 
  })
  .catch(function(err){
     console.log("Error:" + err)
     throw new Error(err) 
  })
}


console.log("------- Test with Fetch/Get/FromWebservice -------")
console.log(getFormattedTime())
var fromLanguage = 'en-US'
var toLanguage = 'es-MX'

getDBLanguagesAndConvertToDataTable(fromLanguage, toLanguage)
    .then(function (dataTable) {
        console.log(getFormattedTime, " Back from call fetch")
        var strDataTable = JSON.stringify(dataTable, null, 3);  
        console.log("ReactTables(): Resulting DataTable=")
        console.log(strDataTable) 
        console.log(getFormattedTime(), "The end of tests ")    

})

我运行“node test.js”。它显示以下内容并挂起。我得休息一下才能结束这一切。

------- Test with Fetch/Get/FromWebservice -------
2020-08-26-20-43-08
Function: 2020-08-26-20-43-08

第2部分-添加捕获后

修订守则:

function getDBLanguagesAndConvertToDataTable(fromLanguage, toLanguage) { 
  // TODO implement from/to Language in URL below  
  console.log("Function: " + getFormattedTime())
  return fetch('http://localhost:3001/api/gettranslations/en-US/es-MX', {
                  method: 'GET',
                  headers: {
                    'Accept': 'application/json',
                    'Content-Type': 'application/json'
                  }
    })
  .then(function(data) {
     // do something with the data 
     console.log("Status:", data.status)
     console.log("data from Fetch:")
     console.log(JSON.stringify(data)) 
     console.log("data.json():")
     console.log(JSON.stringify(data.json())) 
 
     //var tmpDataTable = convertMongoLanguagesToDataTable(data.json())
     //return tmpDataTable
     return data.json() 
  })
  .catch(function(err){
     console.log("Fetch Error:" + err)
     throw new Error(err) 
  })
}

/*
console.log("------- Test with variable data-------------")
console.log(getFormattedTime())
dataTable = convertMongoLanguagesToDataTable(dbGetResults) 
var strDataTable = JSON.stringify(dataTable, null, 3);  
console.log("Resulting DataTable=")
console.log(strDataTable) 
console.log("\n\n")
*/ 

console.log("------- Test with Fetch/Get/FromWebservice -------")
console.log(getFormattedTime())
var fromLanguage = 'en-US'
var toLanguage = 'es-MX'

getDBLanguagesAndConvertToDataTable(fromLanguage, toLanguage)
    .then(function (dataTable) {
        console.log(getFormattedTime, " Back from call fetch")
        var strDataTable = JSON.stringify(dataTable, null, 3);  
        console.log("ReactTables(): Resulting DataTable=")
        console.log(strDataTable) 
        console.log(getFormattedTime(), "The end of tests ")    
    .catch(function (err){
        console.log("call function getDBLanguagesAndConvertToDataTable error:", 
                     getFormattedTime(), "The end of tests ")    
        
    })
})

输出:

------- Test with Fetch/Get/FromWebservice -------
2020-8-26-21-31-5
Function: 2020-8-26-21-31-5
Status: 200
data from Fetch:
{"size":0,"timeout":0}
data.body:
{}
Fetch Error:TypeError: body used already for: http://localhost:3001/api/gettranslations/en-US/es-MX
(node:38732) UnhandledPromiseRejectionWarning: Error: TypeError: body used already for: http://localhost:3001/api/gettranslations/en-US/es-MX
    at E:\GitHub\NealWalters\KyleShedCompanyPOC\shedco-backend\test_convert_languages_to_data_table.js:144:12
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
(node:38732) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 3)
(node:38732) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.