How to set environment variables from within package json

Question

How to set some environment variables from within package json to be used with npm start like commands   Here s what I currently have in my package json              scripts          help    tagove help        start    tagove start                I want to set environment variables  like NODE ENV  in the start script while still being able to start the app with just one command  npm start

User · Answer

Because I often find myself working with multiple environment variables, I find it useful to keep them in a separate .env file (make sure to ignore this from your source control). Then (in Linux) prepend export $(cat .env | xargs) && in your script command before starting your app.

Example .env file:

VAR_A=Hello World
VAR_B=format the .env file like this with new vars separated by a line break

Example index.js:

console.log('Test', process.env.VAR_A, process.env.VAR_B);

Example package.json:

{
  ...
  "scripts": {
    "start": "node index.js",

    "env-linux": "export $(cat .env | xargs) && env",
    "start-linux": "export $(cat .env | xargs) && npm start",

    "env-windows": "(for /F \"tokens=*\" %i in (.env) do set %i)",
    "start-windows": "(for /F \"tokens=*\" %i in (.env) do set %i) && npm start",

  }
  ...
}

Unfortunately I can't seem to set the environment variables by calling a script from a script -- like "start-windows": "npm run env-windows && npm start" -- so there is some redundancy in the scripts.

For a test you can see the env variables by running npm run env-linux or npm run env-windows, and test that they make it into your app by running npm run start-linux or npm run start-windows.

User · Answer

This will work in Windows console   quot scripts quot        quot setAndStart quot    quot set TMP test amp  amp  node index js quot      quot otherScriptCmd quot    quot echo  TMP  quot     npm run aaa output  test See this answer for details

User · Answer

Although not directly answering the question I  d like to share an idea on top of the other answers  From what I got each of these would offer some level of complexity to achieve cross platform independency   On my scenario all I wanted  originally  to set a variable to control whether or not to secure the server with JWT authentication  for development purposes   After reading the answers I decided simply to create 2 different files  with authentication turned on and off respectively      scripts          dev    nodemon --debug  index auth js        devna    nodemon --debug  index no auth js         The files are simply wrappers that call the original index js file  which I renamed to appbootstrapper js      index no auth js authentication turned off const bootstrapper   require    appbootstrapper    bootstrapper false      index auth js authentication turned on const bootstrapper   require    appbootstrapper    bootstrapper true    class AppBootStrapper        init useauth              real initialization           Perhaps this can help someone else

User · Answer

suddenly i found that actionhero is using following code  that solved my problem by just passing --NODE ENV production in start script command option   if argv  NODE ENV      null     api env   argv  NODE ENV      else if process env NODE ENV    null     api env   process env NODE ENV      i would really appreciate to accept answer of someone else who know more better way to set environment variables in package json or init script or something like  where app bootstrapped by someone else

User · Answer

UPDATE  This changes in npm v7 due to npm RFC 21   npm  and yarn  passes a lot of data from package json into scripts as environment variables   Use npm run env to see them all   This is documented in https   docs npmjs com misc scripts environment and is not only for  quot lifecycle quot  scripts like prepublish but also any script executed by npm run  You can access these inside code  e g  process env npm package config port in JS  but they re already available to the shell running the scripts so you can also access them as  npm     expansions in the  quot scripts quot   unix syntax  might not work on windows    The  quot config quot  section seems intended for this use     quot name quot    quot myproject quot            quot config quot          quot port quot    quot 8010 quot          quot scripts quot          quot start quot    quot node server js  npm package config port quot        quot test quot    quot wait-on http   localhost  npm package config port   amp  amp  node test js http   localhost  npm package config port  quot        An important quality of these  quot config quot  fields is that users can override them without modifying package json    npm run start   gt  myproject 0 0 0 start  home cben mydir  gt  node server js  npm package config port  Serving on localhost 8010    npm config set myproject port 8020   git diff package json    no change    cat    npmrc myproject port 8020    npm run start   gt  myproject 0 0 0 start  home cben mydir  gt  node server js  npm package config port  Serving on localhost 8020  See npm config and yarn config docs  It appears that yarn reads    npmrc so npm config set affects both  but yarn config set writes to    yarnrc  so only yarn will see it  -

User · Answer

I just wanted to add my two cents here for future Node-explorers  On my Ubuntu 14 04 the NODE ENV test didn t work  I had to use export NODE ENV test after which NODE ENV test started working too  weird  On Windows as have been said you have to use set NODE ENV test but for a cross-platform solution the cross-env library didn t seem to do the trick and do you really need a library to do this  export NODE ENV test    set NODE ENV test amp  amp  yadda yadda  The vertical bars are needed as otherwise Windows would crash on the unrecognized export NODE ENV command  I don t know about the trailing space  but just to be sure I removed them too

User · Answer

Just use NPM package cross-env  Super easy  Works on Windows  Linux  and all environments  Notice that you don t use  amp  amp  to move to the next task  You just set the env and then start the next task  Credit to  mikekidder for the suggestion in one of the comments here    From documentation        scripts          build    cross-env NODE ENV production OTHERFLAG myValue webpack --config build webpack config js          Notice that if you want to set multiple global vars  you just state them in succession  followed by your command to be executed   Ultimately  the command that is executed  using spawn  is   webpack --config build webpack config js   The NODE ENV environment variable will be set by cross-env

User · Answer

Set the environment variable in the script command       quot scripts quot        quot start quot    quot node app js quot      quot test quot    quot NODE ENV test mocha --reporter spec quot          Then use process env NODE ENV in your app  Note  This is for Mac  amp  Linux only  For Windows refer to the comments

User · Answer

You should not set ENV variables in package json  actionhero uses NODE ENV to allow you to change configuration options which are loaded from the files in   config   Check out the redis config file  and see how NODE ENV is uses to change database options in NODE ENV test  If you want to use other ENV variables to set things  perhaps the HTTP port   you still don t need to change anything in package json   For example  if you set PORT 1234 in ENV and want to use that as the HTTP port in NODE ENV production  just reference that in the relevant config file  IE      in config servers web js exports production        servers        web  function api         return          port  process env PORT

User · Answer

luke s answer was almost the one I needed  Thanks  As the selected answer is very straightforward  and correct   but old  I would like to offer an alternative for importing variables from a  env separate file when running your scripts and fixing some limitations to Luke s answer  Try this       env file       This way  you CAN use comments in your  env files NODE PATH  quot src  quot     You can also have extra empty lines in it SASS PATH  quot node modules src styles quot    Then  in your package json  you will create a script that will set the variables and run it before the scripts you need them      package json     scripts       quot set-env quot    quot export   cat  env   grep   quot         quot   xargs  quot      quot storybook quot    quot npm run set-env  amp  amp  start-storybook -s public quot     Some observations   The regular expression in the grep ed cat command will clear the comments and empty lines   The  amp  amp  don t need to be  quot glued quot  to npm run set-env  as it would be required if you were setting the variables in the same command   If you are using yarn  you may see a warning  you can either change it to yarn set-env or use npm run set-env --scripts-prepend-node-path  amp  amp  instead    Different environments Another advantage when using it is that you can have different environment variables  scripts       quot set-env production quot    quot export   cat  production env   grep   quot         quot   xargs  quot      quot set-env development quot    quot export   cat  env   grep   quot         quot   xargs  quot       Please  remember not to add  env files to your git repository when you have keys  passwords or sensitive personal data in them

User · Answer

use git bash in windows  Git Bash processes commands differently than cmd   Most Windows command prompts will choke when you set environment variables with NODE ENV production like that   The exception is Bash on Windows  which uses native Bash   Similarly  there s a difference in how windows and POSIX commands utilize environment variables  With POSIX  you use   ENV VAR and on windows you use  ENV VAR   - cross-env doc             scripts          help    tagove help        start    env NODE ENV production tagove start                use dotenv package to declare the env variables

User · Answer

For a larger set of environment variables or when you want to reuse them you can use env-cmd      env file     This is a comment ENV1 THANKS ENV2 FOR ALL ENV3 THE FISH     package json        scripts          test    env-cmd mocha -R spec

User · Answer

scripts          start    ENV NODE ENV production someapp --options

User · Answer

Note   In order to set multiple environment variable  script should goes like this    quot scripts quot          quot start quot    quot set NODE ENV production amp  amp  set MONGO USER your DB USER NAME amp  amp  set MONGO PASSWORD DB PASSWORD amp  amp  set MONGO DEFAULT DATABASE DB NAME amp  amp  node app js quot

User · Answer

Try this on Windows by replacing YOURENV                      scripts             help    set NODE ENV YOURENV  amp  amp  tagove help           start    set NODE ENV YOURENV  amp  amp  tagove start

[node.js] How to set environment variables from within package.json?

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