Command Line Parameters causing bad option: --plopfile=plopfile.ts

[awhitford]

Summary

I am trying to pass command-line options to my plop script, but it instead provides an error message:

/usr/local/Cellar/node/22.9.0_1/bin/node: bad option: --plopfile=plopfile.ts
 ELIFECYCLE  Command failed with exit code 9.

I am using a TypeScript plopfile, inspired by #423 and documented here.

How to Reproduce

Create a package.json

{
  "name": "plop-cmd-bug",
  "type": "module",
  "scripts": {
    "plop": "cross-env NODE_OPTIONS='--import tsx' plop --plopfile=plopfile.ts"
  },
  "dependencies": {
    "plop": "^4.0.1",
    "typescript": "^5.6.3"
  },
  "devDependencies": {
    "cross-env": "^7.0.3",
    "tsx": "^4.19.1"
  },
  "packageManager": "pnpm@9.12.1+sha512.e5a7e52a4183a02d5931057f7a0dbff9d5e9ce3161e33fa68ae392125b79282a8a8a470a51dfc8a0ed86221442eb2fb57019b0990ed24fab519bf0e1bc5ccfc4"
}

Create a plopfile.ts

import type { NodePlopAPI } from "plop";

export default function (plop: NodePlopAPI) {
  plop.setGenerator("sample", {
    description: "Sample Generator to show bug with command line arguments.",
    prompts: [
      {
        type: "input",
        name: "name",
        message: "Project Name:",
      },
      {
        type: "input",
        name: "title",
        message: "Project Title:",
      },
    ],
    actions: ["No operation necessary"],
  });
}

Install dependencies

pnpm install

Validate that Prompts Work Fine

Run the plop script and answer the prompts. It will look something like this:

$ pnpm plop sample

> plop-cmd-bug@ plop /Users/anthony/github/awhitford/plop-cmd-bug
> cross-env NODE_OPTIONS='--import tsx' plop --plopfile=plopfile.ts "sample"

? Project Name: my-name
? Project Title: My Title
ℹ No operation necessary

Use Command Line Parameters to Bypass Prompts 🐛

Run the plop script with answers to bypass the prompts. It will look something like this:

$ pnpm plop sample -- --name my-name --title "My Title"

> plop-cmd-bug@ plop /Users/anthony/github/awhitford/plop-cmd-bug
> cross-env NODE_OPTIONS='--import tsx' plop --plopfile=plopfile.ts "sample" "--" "--name" "my-name" "--title" "My Title"

/usr/local/Cellar/node/22.9.0_1/bin/node: bad option: --plopfile=plopfile.ts
 ELIFECYCLE  Command failed with exit code 9.

Interesting Note 🤔

If you only supply name and not title, then it works fine:

$ pnpm plop sample -- --name my-name

> plop-cmd-bug@ plop /Users/anthony/github/awhitford/plop-cmd-bug
> cross-env NODE_OPTIONS='--import tsx' plop --plopfile=plopfile.ts "sample" "--" "--name" "my-name"

? Project Title: My Title
ℹ No operation necessary

Also, if you remove the title from the prompts and simply have the one name prompt left, then that will work fine too:

$ pnpm plop sample -- --name my-name

> plop-cmd-bug@ plop /Users/anthony/github/awhitford/plop-cmd-bug
> cross-env NODE_OPTIONS='--import tsx' plop --plopfile=plopfile.ts "sample" "--" "--name" "my-name"

ℹ No operation necessary

Please help 🛟

[awhitford]

This bug doesn't seem limited to TypeScript because I tried a basic JavaScript version too...

Create a plopfile.js like:

export default function (plop) {
  plop.setGenerator("sample", {
    description: "Sample Generator to show bug with command line arguments.",
    prompts: [
      {
        type: "input",
        name: "name",
        message: "Project Name:",
      },
      {
        type: "input",
        name: "title",
        message: "Project Title:",
      },
    ],
    actions: ["No operation necessary"],
  });
}

Next, tweak the script command in package.json to be plain:

  "scripts": {
    "plop": "plop",
  },

Then, try specifying both parameters:

$ pnpm plop plopfile  -- --name my-name --title "My Title"

> plop-cmd-bug@ plopjs /Users/anthony/github/awhitford/plop-cmd-bug
> plop "plopfile" "--" "--name" "my-name" "--title" "My Title"

⚠️ You will notice that there is no action output. 🐛

This is different than if you don't specify title, like:

$ pnpm plop plopfile  -- --name my-name

> plop-cmd-bug@ plop /Users/anthony/github/awhitford/plop-cmd-bug
> plop "plopfile" "--" "--name" "my-name"

? Project Title: My Title
ℹ No operation necessary

[awhitford]

I traced this problem to the internals of Liftoff, which uses flagged-respawn.

I noticed that the process.argv from line 310 was inconsistent with the argv from line line 312. For example:

>>> Liftoff.prototype.execute: process.argv [
  '/usr/local/Cellar/node/22.9.0_1/bin/node',
  '/Users/anthony/github/awhitford/plop-cmd-bug/node_modules/plop/bin/plop.js',
  'sample',
  '--',
  '--title',
  'My Title',
  '--name',
  'My Nom'
]
>>> Liftoff.prototype.execute: argv [
  '/usr/local/Cellar/node/22.9.0_1/bin/node',
  '--title',
  '/Users/anthony/github/awhitford/plop-cmd-bug/node_modules/plop/bin/plop.js',
  'sample',
  '--',
  'My Title',
  '--name',
  'My Nom',
  '--no-respawning'
]

It appears that the flagged-respawn package is determining that --title should be a node parameter, so it is adjusting the argv. (Where is this documented?)

As a result, I need to change my prompt name to be something else like projectTitle (not title -- because then --title conflicts with node's --title parameter).

Now that I understand what is going on, I will work around this, but this strikes me as unexpected behavior. I wouldn't expect the parameters after -- to be interpreted as potential node parameters. If this can't be fixed, then this nuance should be documented.