If statement not working with a global variable-CodePudding

when using if(typeof(global.payload) == typeof("")) it does not execute the code inside the block even though typeof(global.payload) returns string

my code:

const { uploadFileToCloud } = require("./app.js")
const path = require("path");
var startTime, endTime;
global.payload = null
var download_size = 448800;
console.log("measurement started")
endTime = new Date().getTime()
console.log("start time => "   endTime)


const measureUpSpd = async () => {
  await uploadFileToCloud("uploadPayload.txt", (path.resolve("./").replace(/\\/g, "/")   "/")).then(response => {
    global.payload = response
    console.log("payload => "   global.payload)
    return (response)
  })
};
measureUpSpd().then(x => {
  console.log("payload => "   global.payload   "  ")
})

if (typeof (global.payload) == typeof ("")) {
  console.log("measurement started")
  global.startTime = new Date().getTime();
  console.log("end time => "   startTime);
  ShowData();
  global.payload = null
}

async function ShowData() {
  var duration = (endTime - startTime) / 1000;
  var bitsLoaded = download_size * 8;
  var speedMbps = ((bitsLoaded / duration) / 1024 / 1024).toFixed(2);
  console.log("Speed: "   speedMbps   " Mbps");
}

uploadFileToCloud();

async function uploadFileToCloud(fileName, filePath) {
  try {
    global.filePathPatched = ""   filePath   fileName
    if (filePath) {
      console.log("compete file path is "   filePathPatched)

      var mimetype = await findMimeType(fileName)
      var folderNameParsed = JSON.parse(fs.readFileSync("./settings.json")).folderId
      const response = await drive.files.create({
        requestBody: {
          name: fileName,
          MimeType: mimetype,
          parents: [folderNameParsed]
        },
        media: {
          mimeType: mimetype,
          body: fs.createReadStream(filePathPatched)
        }

      })
      return (response.data.id   "")
    } else {
      console.log("no file path")
    }


  } catch (error) {
    console.log(error.message)
  }
}

CodePudding user response：

measureUpSpd is an async function, that it doesn't seem like you are awaiting. My guess is that the if(typeof(global.payload) == typeof("")) check is occurring before measureUpSpd has completed and actually set global.payload to a string value

CodePudding user response：

This is a very typical case of asynchronous code management.

You either need to place your code in the then callback:

measureUpSpd().then(x => {
  console.log("payload => "   global.payload   "  ")
  if (typeof (global.payload) == typeof ("")) {
    console.log("measurement started")
    global.startTime = new Date().getTime();
    console.log("end time => "   startTime);
    ShowData();
    global.payload = null
  }
})

Or wrap everything in an async IIFE and await the result from measureUpSpd:

(async() => {
  const x = await measureUpSpd();
  console.log("payload => "   global.payload   "  ")

  if (typeof (global.payload) == typeof ("")) {
    console.log("measurement started")
    global.startTime = new Date().getTime();
    console.log("end time => "   startTime);
    ShowData();
    global.payload = null
  }
)();