How to append values to the PATH environment variable in NodeJS?

Question

Following the answer suggested in the question -

Is it possible to permanently set environment variables?

I was able to set new environment variables permanently with the command -

spawnSync('setx', ['-m', 'MyDownloads', 'H:\\temp\\downloads'])

But now my goal is to append new values to the PATH environment variable.

Is it possible?

This seems like a question about Windows and the Setx command, not Node, JavaScript, or Electron. — benbotto, Jan 06 '20 at 15:42
I didn't understand your answer. admin permission is not the problem in my case. — Paz, Jan 13 '20 at 13:33

marksy_91 · Accepted Answer · 2020-01-15T01:28:57.970

3

Why don't you just get the environment variable and then append to it?

I.e.

const {spawnSync} = require("child_process");
const current_value = process.env.PATH;
const new_path_value = current_value.concat(";", "/some/new/path");

var result = spawnSync('setx', ['-m', 'PATH', new_path_value])

// STDOUT
var stdOut = result.stdout.toString();
console.log(stdOut)

// STDERR
var stdErr =  result.stderr.toString();

if(stdErr === '') {
    console.log('Successfully set environment variable')
} else {
    console.log(`ERROR: ${stderr}`)
}

Update "/some/new/path" and run this as admin as the link you provided suggests and it should work.

edited Jan 15 '20 at 01:28

answered Jan 13 '20 at 06:12

marksy_91

196
1
3

Are you able to source the current environment variable from process.env? What happens when you console.log(current_value) and console.log(new_value)? – marksy_91 Jan 14 '20 at 23:21
It was my bad, your solution was correct! thank you very much – Paz Jan 16 '20 at 12:19
I needed to change the line ```console.log(`ERROR: ${stderr}`)``` to ```console.log(`ERROR: ${stdErr}`)``` – mherzog Apr 25 '21 at 13:30

hong4rc · Answer 2 · 2020-01-15T01:56:02.163

2

Run your script with the admin permission:

Open cmd or PowerShell with admin
Run node your_script.js
To append PATH variable, you can set value is : %PATH%;your_new_value here (%PATH% get old value)

If you run with electron app, you should require admin permission.

Don't forget setx run on window

edited Jan 15 '20 at 01:56

answered Jan 03 '20 at 10:32

hong4rc

3,999
4
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What is the difference between appending to an old value and set a new value? – Paz Jan 14 '20 at 21:47
@Paz You can add `%PATH%` to get old value and append your new value – hong4rc Jan 15 '20 at 01:56
Ok, now I understand. That's was the first thing that I did with Electron. I know that the command in windows is setx -m '%path%;NEW_VALUE' but doesn't work with Electron – Paz Jan 15 '20 at 09:35
@Paz do you run it with admin permission? – hong4rc Jan 15 '20 at 09:39
of course. the admin permission is only required for the "-m", meaning the variable will be system variable and not user variable. that's the easy part. I'm always ending up setting a new value that overrides the old one instead of appending a new value. – Paz Jan 15 '20 at 14:12

score 0 · Answer 3 · answered Apr 25 '21 at 14:38

I don't have rights to modify my registry, and I also would rather not call an OS command such as setx.

The following adds an additional component to the Windows PATH. I then ran Selenium, which uses the new setting.

// Display current value of PATH
const current_value = process.env.PATH;
console.log("PREV VALUE:")
console.log(current_value)

// Add the additional entry
const addl_entry = String.raw`\my\new\path\component`
process.env["PATH"] = addl_entry + ";" + current_value

// Display the new value
console.log("NEW VALUE:")
console.log(process.env.PATH)

How to append values to the PATH environment variable in NodeJS?

3 Answers3