使用 .env 文件进行变量赋值

Question

我有一个 .env 文件，看起来像：

NODE_ENV = local
PORT = 4220
BASE_URL = "http://198.**.**.**:4220/"

PROFILE_UPLOAD = http://198.**.**.**:4220/uploads/profile/
POST_UPLOAD = http://198.**.**.**:4220/uploads/discussion/
COMPANY_UPLOAD = http://198.**.**.**:4220/uploads/company/
ITEM_UPLOAD  = http://198.**.**.**/uploads/item/
GROUP_UPLOAD  = http://198.**.**.**/uploads/group/

我想做这样的事情：

NODE_ENV = local
IP = 198.**.**.**
PORT = 5000
BASE_URL = http://$IP:$PORT/

PROFILE_UPLOAD = $BASE_URL/uploads/profile/
POST_UPLOAD = $BASE_URL/uploads/discussion/
COMPANY_UPLOAD = $BASE_URL/uploads/company/
ITEM_UPLOAD  = $BASE_URL/uploads/item/
GROUP_UPLOAD  = $BASE_URL/uploads/group/

的预期结果BASE_URL是http://198.**.**.**:4220/

我尝试了很多语法但没有得到计算值

尝试过的语法："${IP}", ${IP}, $IP

我使用dotenv package 来访问 env 变量。

Answer 1

dotenv-expand是@maxbeatty 回答的解决方案，以下是要遵循的步骤

脚步 ：

首先安装：

npm install dotenv --save
npm install dotenv-expand --save

然后更改 .env 文件，如：

NODE_ENV = local
PORT = 4220
IP = 192.***.**.**
BASE_URL = http://${IP}:${PORT}/

PROFILE_UPLOAD = ${BASE_URL}/uploads/profile/
POST_UPLOAD = ${BASE_URL}/uploads/discussion/
COMPANY_UPLOAD = ${BASE_URL}/uploads/company/
ITEM_UPLOAD  = ${BASE_URL}/uploads/item/
GROUP_UPLOAD  = ${BASE_URL}/uploads/group/

最后一步 ：

var dotenv = require('dotenv');
var dotenvExpand = require('dotenv-expand');

var myEnv = dotenv.config();
dotenvExpand(myEnv);

process.env.PROFILE_UPLOAD; // to access the .env variable

或（更短的方式）

require('dotenv-expand')(require('dotenv').config()); // in just single line
process.env.PROFILE_UPLOAD; // to access the .env variable

Answer 2

dotenv-expand是在 dotenv 之上构建的，旨在解决这个特定问题