Using description returns undefined

[Robert Planas]

This is a weird one. I'm using typescript + pnpm + esbuild. This is my "main.ts" file:

import { Command } from 'commander'
const program = new Command()

program
    .name('example')
    .description(process.env.npm_package_description)
    .version(process.env.npm_package_version)

And the scripts I have in "package.json":

    "scripts": {
        "start": "node dist/esm.js",
        "build": "npm run build:esm",
        "build:esm": "esbuild --bundle src/main.ts --format=esm --platform=node --outfile=dist/esm.js --packages=external",
    },

If I run npm start, it fails with an error:

TypeError: program.name(...).description(...).version is not a function

But if I run it with pnpm start everything works fine. Even more interesing, when I swap the "description" and version order, as in:

program
    .name('example')
    .version(process.env.npm_package_version)
    .description(process.env.npm_package_description)

Then everything works both with npm and pnpm.

Also it seems that using this order hides the description (probably that is why it works), is it supported?

[John Gee]

Both .version() and .description() will return the current value if they are called with no argument, instead of returning the command for another chaining call. I suspect process.env.npm_package_description is undefined and the .description() call is acting as a getter and returning a string.

To avoid the problem without refactoring your code you could call like:

.description(process.env.npm_package_description ?? '')

[Robert Planas]

That explains it. Thanks @shadowspawn.