How can I pass arguments to an nps command?

[dweber019]

• nps version: latest
• node version: lastest
• npm version: lastest

The command executed:

npm start -- --env.platform=mobile
nps serve --env.platform=mobile

The output:

You provided one or more invalid flags: env Did you forget to put your command in quotes?

Or it just runs without applying the argument.

Problem description:

How can I pass arguments to an nps command?
Before I was using npm scripts and there I could pass arguments form the command line like https://docs.npmjs.com/cli/run-script.

This is not possible or at least not documented.

Use case:

I like to provide something dynamically to the command. E.g. the name of a configuration file.
I don't like to configure for each dynamic option an nps command and in addition, to be user friendly, I would also have to configure all the npm scripts for each nps command.

Suggested solution:

Add the same option as npm-script does to support passing arguments from the command line.

[kentcdodds]

Try:

nps "serve --env.platform=mobile"

[dweber019]

Nice I know now that I can do:

nps "serve --env.platform=mobile"

Putting the command in " solves the problem in nps

[kentcdodds]

Thanks for using nps and filing an issue. If there's something that could be improved with the docs, please make a pull request: http://makeapullrequest.com

[dweber019]

@kentcdodds How can I do the same over npm e.g.:

npm start -- --env.platform=mobile

Or do I have to use strictly nps now?

Would be nice if the user could just rely on the defaulting behavior and just pass an argument at the very beginning.

[kentcdodds]

Hmmm.... That's a use case I hadn't considered. Most of the time you just make it a script (for example, call it mobile) and run: npm start mobile

[dweber019]

Yes but if there is dynamic parameter, there is ability to pass without writing the full nps command path.

I would be nice if I could run:

npm start -- --env.platform=mobile
npm run build -- --env.platform=mobile

without knowing the whole nps logic/path. It would be nice for Developers which have nothing to do with the build/runtime process.

Totally get your npm start mobile suggestion but imagine I have two options --env.platform and --env.config which can be combined. I would end up with a lot of npm scripts without changing the base command in nps, just the arguments change.

[kentcdodds]

Try: ./node_modules/.bin/nps "serve --env.platform=mobile" 👍

[dweber019]

Doesn't solve my issue of being dynamic from the command line but it definitely solves some issues in the nps configuration file.

[kentcdodds]

Doesn't solve my issue of being dynamic from the command line

Could you explain what you mean?

[dweber019]

The comment from @gunnx in this issue #101 is what I mean (or at least it describes the npm-script argument issue). There is no possibility to pass any kind of custom argument to nps without using the full nps command path and using nps directly.

So I can't do this:

npm run <any-script> -- --myargument=example

Because the double quote won't work as the nps command is behind the npm-script.

And I can't do this:

nps "mobile.build --myargument=example"

When the targeted full command path is mobile.build.development. Even when the default behavior is setup to reach command mobile.build.development by just typing mobile.build.

Summary:

1. No argument passing over npm-scripts at all
2. No argument passing over nps default behavior. So as soon as there is an argument involved I can't leverage the default behavior system.
3. Ending up in building a lot of commands/option entries because I have to cover all my possible argument combinations

But I think currently there isn't any solution for my problem. So it's more of a feature/enhancement to be considered in the future ;)

[kentcdodds]

Ok, let's talk about how to solve this problem. What do you mean by:

And I can't do this:

nps "mobile.build --myargument=example"

[dweber019]

Let's do it ;)

Imagine this configuration:

module.exports = {
  scripts: {
    default: 'nps mobile',
    mobile: {
      default: 'nps mobile.build',
      build: {
        default: 'nps mobile.build.development',
        development: 'any command'
      }
    }
  }
}

In the end I like to call mobile.build.development any time.

I can do this currently by calling:

nps
nps mobile
nps mobile.build
nps mobile.build.development

Now I would like to pass a custom argument to the command behind mobile.build.development.

Suddenly, I can only do this by calling nps "mobile.build.development --argumentname=value" directly. So no defaulting anymore.

I can't do this because the behavior changed to:

nps --argumentname=value" // Not working anymore
nps "mobile --argumentname=value" // Not working anymore
nps "mobile.build --argumentname=value" // Not working anymore
nps "mobile.build.development --argumentname=value" // Still working

[gunnx]

@dweber019 Yeah there's a few occasions where I really miss the option to do this, I've got around it for most things by creating specific package-scripts entries to cover the common flags. It's where you want to pass dynamic values that it falls down, for example in my BDD test framework I have the option to running certain tags by passing them as a value but there are lots of tags and you can pass multiple tags or conditional tags, something thats just not realistic to be done via package-scripts.

some examples:

npm start -- --tags 'not @skip'
npm start -- --tags '@smoke and not @skip'
npm start -- --tags '@CI and not @skip'
npm start -- --tags '(@smoke or @ui) and (not @slow)'

I understand the reason to remove this was the confusion about whether to pass or not, would it be possible to have a new flag for nps that then passes that down to the actual command.

[dweber019]

@gunnx your suggestion about a new flag would be awesome.

Btw. I could solve my npm run issue.
If I have the following npm script:

"scripts": {
    "start": "nps"
}

I can pass arguments like npm start -- "mobile.build.development --argumentname=value".

So only the argument passing nps internally over defaulting behaviors is an issue.

[kentcdodds]

I'm really sorry that I'm struggling to understand the issue. Could you explain what you meant by:

Would be nice if the user could just rely on the defaulting behavior and just pass an argument at the very beginning.

What if we exposed an additional binary (nps-raw?) that behaves similar to the old binary. The behavior would be that it doesn't accept any flags of its own and all flags are forwarded to the command:

nps-raw serve --foo=bar --baz --buzz=foobar

Would that solve the use-case?

[dweber019]

I don't think this will fix the defaulting issue.

The custom argument should be passed from default command to default command until the final command is reached.

[kentcdodds]

I think that it would. If you used nps-raw exclusively even in your package-scripts.js file, then I believe that it would fix the issue.

Would you like to try it out and makeapullrequest.com? :)

[kwelch]

I am running into the same issue. I will try to explain it a little differently and hopefully provide a solution.

Script I am running
npm start build -- --build {CI_BUILD_NUMBER}

Script processed as
nps build "--" "--build" "{CI_BUILD_NUMBER}"

Ideally processed as
nps "build --build {CI_BUILD_NUMBER}"

Although extracting nps-raw would work, the potential simpler solution (from the outside looking in) would be to treat anything after "--" as an option flag. This may be a breaking change, but I am not sure, since any point that "--" is found nps will throw the invalid flag(s) passed: error.

[kentcdodds]

Yeah, I think we'd be safe to call that a patch. If you'd like to implement that, I'd happily accept 👍

[kwelch]

This should be closable. Only potential dependency would be documentation.

[kentcdodds]

Whoops, forgot to ask you to document that in your PR. Could you do that really quick? Then we can close this. Thanks @kwelch!

[kwelch]

So looking back at this to add docs, and the unit tests passes, but the functionality added in #138 does not work when called. I am starting to look into #139 instead.

[kentcdodds]

Good call 👍

[xenoterracide]

I want this too, use case is local dev using npm start which runs via nps, a webpack-dev-server, would like to simply change the port, e.g. npm start --port 8000, although making a static for the port wouldn't be hard, it's really not efficient to make a different configuration every time a dev wants to change something like a port. could it be passed via an env var? sure, but this doesn't seem like the right design to me.

[GarthDB]

This is exactly what I'm looking for. My primary use case is using it for isolating specific tests: npm test -- --watch --match='test name'

I see a solution was merged, but I'm looking for the documentation because I can't seem to get it to work the way I expect.

[dkent600]

@GarthDB Looks like it was merged but hasn't been published yet

[kentcdodds]

All my packages are automatically published. If it hasn't been published then something went wrong with the build.

[infctr]

Given the following config:

module.exports = {
  scripts: {
    test: {
      default: 'jest --config jest/config.js',
    },
  },
}

Got passing arguments to work like this yarn nps "test -u"

[Venryx]

To clarify on usage, here is an example package-scripts.js:

const scripts = {
	myScript: "echo Hi",
};
module.exports.scripts = scripts;

Example usage: (without "--")

(base) PS C:\Test> npm start "myScript myArg"   

> [email protected] start C:\Test
> nps "myScript myArg"

nps is executing `myScript` : echo Hi myArg
Hi myArg

Example usage: (with "--")

> [email protected] start C:\Test
> nps "myScript -- myArg"

nps is executing `myScript` : echo Hi -- myArg
Hi -- myArg