NodeJS - Can I detect when called from command line (ES6 + Babel)..?

Question

In my module I need to detect when it's being called from either the command line, or from another module.

const isFromCLI = '????'

I'm using Babel/ES6, so when called from a command line, index.js is called (with the babel code), which hands off to script.js (with ES6 code). So from the script file, module.parent returns module (the index.js file). So I can't use module.parent!

Also, module.main is undefined (in script.js) when called from either the command line or from another module. So I can't use module.main!

Those are the two solutions that others are suggesting, but they don't work for me.

Is there a simple to detect this when using Babel/ES6..?

Update

require.main returns module when called from either the command line or from another module.

Please show us how you are invoking the code. If, as you say, index.js is called from the command line which hands off to script.js, then script.js is not called directly from the command line? Seems fine to me. — Bergi
– Bergi, Commented Mar 10, 2017 at 14:17
@Bergi You're correct, script.js is not called directly from the command line. However index.js only contains the Babel code required for script.js to work. I see what you're saying though. I thought there might be a different way to detect this, rather than seeing if module.parent is equal to module. — Stephen Last
– Stephen Last, Commented Mar 10, 2017 at 14:24

Frank V · Accepted Answer · 2017-03-10 14:24:33Z

You could use Process in Node.

https://nodejs.org/api/process.html#process_process_argv

Check the value of the second parameter (do a contains type match). Not sure if this is the only way but it's a straight forward way to achieve what you need

A code snippet might be:

 const isFromCLI = (process.argv[1].indexOf('my-script.js') !== -1);

This does work, the second element is the path to the js file being executed, which in my case is different. It's a bit of a work around, but does work.

Raphael Rafatpanah · Accepted Answer · 2017-03-10 15:34:37Z

You can use Node Environment Variables.

You can set an environment variable like this:

CLI=true node app.js

and then get the environment variable like this:

const isFromCLI = process.env.CLI === 'true'

Note: process.env.CLI will be a string.

Update:

If you want to do something like node app.js --cli, you can do the following:

let isFromCLI process.argv.forEach(function (val, index, array) { if (array[index] === '--cli') { isFromCLI = true } }) console.log(isFromCLI)

This would work, however, ideally I want to avoid changing what I use on the command line. I could just as easy add an cli option node app.js --cli.

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