Add support for cascading .env files in webpapck project.
For documentation on which .env files can be used, see: https://facebook.github.io/create-react-app/docs/adding-custom-environment-variables#adding-development-environment-variables-in-env
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.env support for webpack - based on code from create-react-app
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| # example of a config value | |
| REACT_APP_EXAMPLE_VAL=1234 |
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| // based on https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/config/env.js | |
| 'use strict'; | |
| const fs = require('fs'); | |
| const path = require('path'); | |
| // originally from paths.js | |
| const appDirectory = fs.realpathSync(process.cwd()); | |
| const resolveApp = relativePath => path.resolve(appDirectory, relativePath); | |
| const paths = { | |
| dotenv: resolveApp('.env'), | |
| } | |
| // Make sure that including paths.js after env.js will read .env variables. | |
| // delete require.cache[require.resolve('./paths')]; | |
| const NODE_ENV = process.env.NODE_ENV; | |
| if (!NODE_ENV) { | |
| throw new Error( | |
| 'The NODE_ENV environment variable is required but was not specified.' | |
| ); | |
| } | |
| // https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use | |
| var dotenvFiles = [ | |
| `${paths.dotenv}.${NODE_ENV}.local`, | |
| `${paths.dotenv}.${NODE_ENV}`, | |
| // Don't include `.env.local` for `test` environment | |
| // since normally you expect tests to produce the same | |
| // results for everyone | |
| NODE_ENV !== 'test' && `${paths.dotenv}.local`, | |
| paths.dotenv, | |
| ].filter(Boolean); | |
| // Load environment variables from .env* files. Suppress warnings using silent | |
| // if this file is missing. dotenv will never modify any environment variables | |
| // that have already been set. | |
| // https://github.com/motdotla/dotenv | |
| dotenvFiles.forEach(dotenvFile => { | |
| if (fs.existsSync(dotenvFile)) { | |
| require('dotenv').config({ | |
| path: dotenvFile, | |
| }); | |
| } | |
| }); | |
| // We support resolving modules according to `NODE_PATH`. | |
| // This lets you use absolute paths in imports inside large monorepos: | |
| // https://github.com/facebookincubator/create-react-app/issues/253. | |
| // It works similar to `NODE_PATH` in Node itself: | |
| // https://nodejs.org/api/modules.html#modules_loading_from_the_global_folders | |
| // Note that unlike in Node, only *relative* paths from `NODE_PATH` are honored. | |
| // Otherwise, we risk importing Node.js core modules into an app instead of Webpack shims. | |
| // https://github.com/facebookincubator/create-react-app/issues/1023#issuecomment-265344421 | |
| // We also resolve them to make sure all tools using them work consistently. | |
| // const appDirectory = fs.realpathSync(process.cwd()); | |
| process.env.NODE_PATH = (process.env.NODE_PATH || '') | |
| .split(path.delimiter) | |
| .filter(folder => folder && !path.isAbsolute(folder)) | |
| .map(folder => path.resolve(appDirectory, folder)) | |
| .join(path.delimiter); | |
| // Grab NODE_ENV and REACT_APP_* environment variables and prepare them to be | |
| // injected into the application via DefinePlugin in Webpack configuration. | |
| const REACT_APP = /^REACT_APP_/i; | |
| function getClientEnvironment(publicUrl) { | |
| const raw = Object.keys(process.env) | |
| .filter(key => REACT_APP.test(key)) | |
| .reduce( | |
| (env, key) => { | |
| env[key] = process.env[key]; | |
| return env; | |
| }, | |
| { | |
| // Useful for determining whether we’re running in production mode. | |
| // Most importantly, it switches React into the correct mode. | |
| NODE_ENV: process.env.NODE_ENV || 'development', | |
| // Useful for resolving the correct path to static assets in `public`. | |
| // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />. | |
| // This should only be used as an escape hatch. Normally you would put | |
| // images into the `src` and `import` them in code to get their paths. | |
| PUBLIC_URL: publicUrl, | |
| } | |
| ); | |
| // Stringify all values so we can feed into Webpack DefinePlugin | |
| const stringified = { | |
| 'process.env': Object.keys(raw).reduce( | |
| (env, key) => { | |
| env[key] = JSON.stringify(raw[key]); | |
| return env; | |
| }, | |
| {} | |
| ), | |
| }; | |
| return { raw, stringified }; | |
| } | |
| module.exports = getClientEnvironment; |
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| const webpack = require('webpack'); | |
| const getClientEnvironment = require('./env'); | |
| // Read values from .env files | |
| const publicUrl = ''; | |
| const env = getClientEnvironment(publicUrl); | |
| // example for accessing a value in webpack config | |
| const exampleVal = env.raw.REACT_APP_EXAMPLE_VAL; | |
| const config = { | |
| // ... | |
| plugins: [ | |
| //..., | |
| new webpack.DefinePlugin(env.stringified) | |
| //..., | |
| ] | |
| //... | |
| }; | |
| module.exports = config; |
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