将函数的特定变量导出到另一个文件答案

【问题标题】：Export the particular variable of function to another file将函数的特定变量导出到另一个文件
【发布时间】：2019-09-08 19:04:12
【问题描述】：

我有一个查询，这就是我如何将“userURL”变量从下面的文件（imageController.js）发送到另一个文件（contactController.js）。一件事我只想发送“userURL”变量而不是整个函数“resize”。我尝试通过使用“module.exports”来解决这个问题，但我遇到的问题是“module.exports”发送整个函数“resize”而不是“userURL”变量。现在在第二个文件“contactController.js”中，我在 console.log 中提到了 {userURL}，但它只打印“你的结果未定义”。我只想将 userURL 从第一个文件 imageController.js 导出到第二个文件“contactController.js”。


imageController.js


exports.resize = async (req, res, next) => {
 if(!req.file){
   next()
   return
 }

  const extension = req.file.mimetype.split('/')[1]
  req.body.userFile = `${uuid.v4()}.${extension}`
  const photo = await jimp.read(req.file.buffer)
                await photo.resize(500, jimp.AUTO)
                await photo.write(`./public/uploads/${req.body.userFile}`)
  const userimg = photo; 




  console.log(`./public/uploads/${req.body.userFile}`)

  cloudinary.config({
    cloud_name: 'katal',
    api_key: process.env.API_KEY,
    api_secret: process.env.API_SECRET
    }); 

  cloudinary.v2.uploader.upload(`./public/uploads/${req.body.userFile}`,{ 
  transformation: { width:100, height:100}}, function(error, result) { 
  console.log('please show result\t' +JSON.stringify(result))

    const userURL ='vikivivki'



    res.send(result.secure_url)
    console.log(result.secure_url)
})
}


contactController.js

const mongoose = require('mongoose')
const Contact = mongoose.model('Contact')
const moment = require('moment-timezone') 
const {userURL} = require('./imageController')


exports.contactForm = (req, res) => {
  res.render('contact')
} 

exports.usermessage = async(req, res) => {

      req.body.name =  req.body.name 
      req.body.email = req.body.email 
      req.body.message = req.body.message 
      const ind = moment.tz(Date.now(), "Asia/Calcutta")

      const newContact = new Contact(req.body)
      await newContact.save() 

      console.log('your result',userURL)


      let showResult1 = JSON.stringify(newContact)
      let showResult = JSON.parse(showResult1)
      res.send(showResult.message)

    }

【问题讨论】：

exports.userURL ='vikivivki'
我如何在另一个文件中只导入这个变量@joyBlanks
const {userURL} = require('./imageController.js')
成功了吗？让我知道你需要更多帮助吗？
它工作正常，但打印未定义

标签： javascript node.js ecmascript-6

【解决方案1】：

您需要导出您需要访问的项目

exports.userURL ='vikivivki'; //exporting here along with rezise as well

文件 imageController.js

//imageController.js

exports.userURL ='vikivivki'; //exporting here along with rezise as well

exports.resize = async (req, res, next) => {
 if(!req.file){
   next()
   return
 }

  const extension = req.file.mimetype.split('/')[1]
  req.body.userFile = `${uuid.v4()}.${extension}`
  const photo = await jimp.read(req.file.buffer)
                await photo.resize(500, jimp.AUTO)
                await photo.write(`./public/uploads/${req.body.userFile}`)
  const userimg = photo; 




  console.log(`./public/uploads/${req.body.userFile}`)

  cloudinary.config({
    cloud_name: 'katal',
    api_key: process.env.API_KEY,
    api_secret: process.env.API_SECRET
    }); 

  cloudinary.v2.uploader.upload(`./public/uploads/${req.body.userFile}`,{ 
  transformation: { width:100, height:100}}, function(error, result) { 
  console.log('please show result\t' +JSON.stringify(result))

    const userURL ='vikivivki'



    res.send(result.secure_url)
    console.log(result.secure_url)
})
}

在您的 contactController.js

中

//contactController.js

const mongoose = require('mongoose')
const Contact = mongoose.model('Contact')
const moment = require('moment-timezone') 
const {userURL} = require('./imageController'); // Please have a check on location if they are in the same directory


exports.contactForm = (req, res) => {
  res.render('contact')
} 

exports.usermessage = async(req, res) => {

      req.body.name =  req.body.name 
      req.body.email = req.body.email 
      req.body.message = req.body.message 
      const ind = moment.tz(Date.now(), "Asia/Calcutta")

      const newContact = new Contact(req.body)
      await newContact.save() 

      console.log('your result',userURL)


      let showResult1 = JSON.stringify(newContact)
      let showResult = JSON.parse(showResult1)
      res.send(showResult.message)

    }

【讨论】：