Question

我正在努力将自己的.env文件加载到NextJS应用程序中。这是我的代码：

我的.env在根/中
我的index.js在/pages/index.js

中

这是我的index.js：

require("dotenv").config({ path: __dirname + '/../.env' })

import React, {Component} from 'react'
import Layout from '../components/layout'
import axios from 'axios'

class Import extends Component{

    uploadCSV = (evt) => {
        evt.preventDefault();

        const uploadURL = process.env.MY_UPLOAD_URL

        let data = new FormData(evt.target)

        axios.post(uploadURL, data, {
            headers: {
                'Content-Type': 'multipart/form-data'
            }
        }).then((res) => {
            console.log(res)
        })
    }

    render() {
        return (
            <div>
                <Layout title="Import Chatbot Intents" description="Import Chatbot Intents">
                    <form onSubmit={this.uploadCSV} name="import_csv" className="import_csv">
                        <h2>Import CSV</h2>
                        <div className="form-group">
                            <label htmlFor="csv_file">Upload file here: </label>
                            <input type="file" name="csv_file" id="csv_file" ref="csv_file" />
                        </div>
                        <div className="form-group">
                            <input type="hidden" id="customer_id" name="customer_id" ref="customer_id" value="1"/>
                            <button className="btn btn-success">Submit</button>
                        </div>
                    </form>
                </Layout>
            </div>
        )
    }
}

export default Import

我注意到我可以在.env函数中打印出render()内容，但是在uploadCSV函数中却不能打印出来。

有关您的信息：

仅使用require("dotenv").config()无效
使用require("dotenv").config({path: "../"})无效

已更新

我的env-config.js：

module.exports = {
    'CSV_UPLOAD_URL': "http://localhost:3000/uploadcsv"
}

我的babel.config.js：

const env = require('./env-config')
console.log(env)

module.exports = function(api){

  // console.log({"process": process.env})
  api.cache(false)

  const presets = [
    "next/babel",
    "@zeit/next-typescript/babel"
  ]

  const plugins = [

      "@babel/plugin-transform-runtime",
      [
        'transform-define',
        env
      ]
  ]

  return { presets, plugins }
}

我的package.json

{
  "name": "Botadmin",
  "scripts": {
    "dev": "next -p 3001",
    "build": "next build",
    "start": "next start"
  },
  "dependencies": {
    "@babel/runtime": "^7.1.5",
    "@zeit/next-less": "^1.0.1",
    "@zeit/next-typescript": "^1.1.1",
    "@zeit/next-workers": "^1.0.0",
    "axios": "^0.18.0",
    "forever": "^0.15.3",
    "less": "^3.8.1",
    "multer": "^1.4.1",
    "next": "7.0.2",
    "nprogress": "^0.2.0",
    "papaparse": "^4.6.2",
    "react": "16.6.3",
    "react-dom": "16.6.3",
    "typescript": "^3.1.6",
    "worker-loader": "^2.0.0"
  },
  "devDependencies": {
    "@babel/plugin-transform-runtime": "^7.1.0",
    "babel-plugin-transform-define": "^1.3.0",
    "dotenv": "^6.1.0",
    "fork-ts-checker-webpack-plugin": "^0.4.15"
  }
}

错误：

Module build failed (from ./node_modules/next/dist/build/webpack/loaders/next-babel-loader.js):
TypeError: Property property of MemberExpression expected node to be of a type ["Identifier","PrivateName"] but instead got "StringLiteral"

Answer 1

从Next.js 9.4开始，有一个内置的解决方案用于设置环境变量https://nextjs.org/docs/basic-features/environment-variables

Answer 2

感谢@Alex的回答。解决同一问题的另一种方法是使用dotenv-webpack安装npm install -D dotenv-webpack。

一旦安装。编辑next.config.js：

require('dotenv').config()
const Dotenv = require('dotenv-webpack')

const path = require('path')

const withTypescript = require('@zeit/next-typescript')
const withWorkers = require('@zeit/next-workers')
const withLess = require('@zeit/next-less')

module.exports = withWorkers(withLess(withTypescript({
    context: __dirname,
    generateEtags: false,
    entry: './pages/index.js',
    distDir: 'build',
    pageExtensions: ['js', 'jsx', 'ts', 'tsx'],

    cssModules: false,

    webpack: (config, options) => {

        config.plugins = config.plugins || []

        config.plugins = [
            ...config.plugins,

            // Read the .env file
            new Dotenv({
                path: path.join(__dirname, '.env'),
                systemvars: true
            })
        ]

        // Fixes npm packages that depend on `fs` module
        config.node = {
            fs: 'empty'
        }

        return config
    }
})))

Answer 3

如果您想使用env in Nextjs

安装babel-plugin-transform-define

创建env-config.js文件并定义变量

const prod = process.env.NODE_ENV === 'production'
module.exports = {
 'process.env.BACKEND_URL': prod ? 'https://api.example.com' : 'https://localhost:8080'
}

创建.babelrc.js文件

const env = require('./env-config.js')

module.exports = {
 presets: ['next/babel'],
 plugins: [['transform-define', env]] 
}

现在您可以在代码中访问环境了
```
 process.env.BACKEND_URL
```

替代方法：next-env

未在nextjs中加载dotenv值

3 个答案: