Is there a way to run "nvm use" automatically in a prestart npm script?

Question

I would like to have automatically invoked "nvm use" when I run "npm start". So I come up with this solution:

package.json file

"scripts": {
  "prestart": "sh test.sh",
  "start": "nodemon index.js"
}

.nvmrc file

test.sh file

#!/bin/bash

if [ -d ~/.nvm ]
  then
    source ~/.nvm/nvm.sh

    nvm use
fi

This works and switches between nvm versions console output is:

> sh test.sh

Found '/my-user-path/.nvmrc' with version <4>
Now using node v4.2.2 (npm v2.14.7)

> app@1.0.0 start /app-path/
> nodemon index.js

But when I call form index.js "console.log(process.versions);" nvm script is executed probably in different process so output is:

{ 
  http_parser: '2.6.0',
  node: '5.1.0',
  v8: '4.6.85.31',
  uv: '1.7.5',
  zlib: '1.2.8',
  ares: '1.10.1-DEV',
  icu: '56.1',
  modules: '47',
  openssl: '1.0.2d' 
}

Any suggestions on how to deal with this in a proper way?

Thanks

Related: https://stackoverflow.com/q/23556330/320399 – blong Feb 24 '21 at 18:41 — blong, Feb 24 '21 at 18:41

score 28 · Answer 1 · answered Apr 11 '16 at 16:02

28

Generally on a Mac, the nvm.sh file is located in your home path. Use the $HOME variable if you have multiple Mac users working on the code.

"scripts": {
    "prestart": "source $HOME/.nvm/nvm.sh; nvm use"
}

I would've added this as a comment to the above response, but I'm not allowed :(

answered Apr 11 '16 at 16:02

Ribbo

399
3
11

3

This doesn't work in a prestart script. It has to be in the start script, per @LLeo's answer. – Jonathon Hill Jan 08 '18 at 15:31
1

I had to add `unset PREFIX;` to the start of the command to make it work. thanks! – Norfeldt Jan 19 '21 at 07:37
@JonathonHill Is that still true today? No reason to doubt, other than NodeJS/npm evolution – blong Feb 16 '21 at 17:27
1

Similar to @norfeldt, I added `--delete-prefix`. Whole script: `source $HOME/.nvm/nvm.sh; nvm use --delete-prefix` – joematune Dec 08 '21 at 08:59

score 13 · Answer 2 · edited Feb 24 '21 at 19:55

13

Your package.json could look like

"scripts": {
    "start": "source /whereever/located/nvm.sh; nvm use; nodemon index.js"
}

To explain. The "start" line is a single shell instance. So you have to have nvm initialize the PATH in that shell instance. Also, nvm is a shell function not an executable shell script. The nvm function lives in the shell instance, and is created by sourcing the nvm.sh file.

Sorry for the edits cuz I didn't test my first two.

edited Feb 24 '21 at 19:55

blong

2,815
8
44
110

answered Dec 16 '15 at 20:35

LLeo

131
4

Thank you @LLeo. This worked best for me because I was able to create my own script that wouldn't affect my team members since I don't know who has nvm and if it's installed in the same location as everyone else. I didn't test it but by the name, prestart would affect all scripts which is not wanted in my case. – Devin Ledesma Dec 10 '20 at 19:46
1

I did have a question about your answer though. Is using a semicolon equivalent to using double ampersand? `; => &&` I tried both ways and they worked. Just was hoping to understand the differences, if there are any other than aesthetics – Devin Ledesma Dec 10 '20 at 19:48
4

Semicolon is just a command separator in shell. "&&" executes the rest of the line only if the command on the left return "true" which is exit code 0 (non-zero if false). – LLeo Dec 12 '20 at 02:13
1

Thank you @LLeo. Once again I appreciate your great answers :) – Devin Ledesma Dec 16 '20 at 02:19

user6260563 · Answer 3 · 2022-11-09T10:22:09.850

2

for mac eg :

"scripts": {
    "dev": "source $HOME/.nvm/nvm.sh; nvm use;nvm use v14.17.5 && cross-env ENV_TYPE=localhost umi dev"
  },

edited Nov 09 '22 at 10:22

answered Oct 29 '21 at 02:50

user6260563

21
3

it seems it calls itself at the end – Luckylooke Jul 22 '22 at 13:04

Is there a way to run "nvm use" automatically in a prestart npm script?

3 Answers3

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