How do I pass the result from a command to another command's option in a single npm run script?

Question

I'm not sure whether this is possible in a single line, but I want to run yaml2json and pass the result json to jade -O option in CLI.

I know if I write the json file and specify the output file path in -O option, it works. But I would rather not write some temporary file if this can be done without it.

So This works

{
  "scripts": {
    "jade": "yaml2json src/data/site.yaml > temp.json && jade src/jade/pages --out dist -O temp.json",
  }
}

However this doesn't.

{
  "scripts": {
    "jade": "jade src/jade/pages --out dist -O yaml2json src/data/site.yaml"
  }
}

Any help or insight would be appreciated.

Answer 1

Have you tried using backticks (the grave)?

{
  "scripts": {
    "jade": "jade src/jade/pages --out dist -O \"`yaml2json src/data/site.yaml`\""
  }
}

Or you could remove the temporary file afterwards if it is lingering (Linux/OSX only):

{
  "scripts": {
    "jade": "yaml2json src/data/site.yaml > temp.json && jade src/jade/pages --out dist -O temp.json && rm temp.json",
  }
}