Feature request: wait for message on stdout before continuing

[poislagarde]

Hey! I'm setting up a node server with TypeScript, and I'd like to spawn tsc -w (compile + watch .ts files) in parallel with nodemon (watch compiled .js files + restart server).
The problem is that I need to delay the spawning of nodemon until tsc is done compiling.

I think it would be very useful if we could tell npm-run-all to wait for a message to appear on stdout before continuing to spawn tasks.

What do you think? If you guys think it's a good idea I can try to put together a PR. Of course I could use some pointers in that case.

[mysticatea]

Thank you for this issue.

Hmm, sorry, I don't want to add the feature to wait for specified message.
I think it's too complex for CLI option.

There are some workarounds.

1. Does the first build before watching.

   {
       "build": "tsc ...",
       "watch": "npm-run-all build -p watch:*",
       "watch:tsc": "tsc -w ...",
       "watch:nodemon": "nodemon ..."
   }

2. Wait for built files in nodemon command.
   https://stackoverflow.com/questions/37466757/how-do-i-run-postmans-newman-in-ci-environment
   wait-on command can wait for local files.

[poislagarde]

I understand, it could get a little messy. Thank you for the quick answer and help though, and wait-on works great in my case. Thanks again!

[robario]

@mysticatea
I know how @poislagarde feel.

{
    "build": "webpack",
    "watch": "npm-run-all build -p watch:*",
    "watch:webpack": "webpack --watch",
    "watch:depends_on_webpack": "some_processing ./www/bundle.js",
}

In the case of above, webpack's first build runs twice. (And the first build is slower than the continuous build.)
The idea of using wait-on sounds good.

    "watch:depends_on_webpack": "wait-on ./www/bundle.js && some_processing ./www/bundle.js",

However it is not waiting if ./www/bundle.js already exists.
I want to wait for the completion of the process rather than the file creation.

Should I do like this?

    "watch:depends_on_webpack": "rimraf ./www/bundle.js && wait-on ./www/bundle.js && some_processing ./www/bundle.js",

Otherwise wait for the stdout as described in this issue?
However, I think it is difficult that implement to wait for stdout.

[poislagarde]

@robario if it helps, I ended up doing this:

"scripts": {
    "prebuild": "rimraf _built",
    "build": "tsc",
    "watch": "npm-run-all prebuild -p watch:*",
    "watch:tsc": "tsc -w",
    "watch:nodemon": "wait-on _built/server.js && nodemon _built/server.js --watch _built"
}

wait-on works fine here because the _built directory is cleared (rimraf _built) before.

[robario]

@poislagarde
Thank you for telling me the actual situation.
I started using rimraf and wait-on, too.

[mysticatea]

Closing as I don't want to add this feature.
Thank you for making request.