node.jsnpmpackage.jsonyarnpkgnpm-scripts

Pass command line -- argument to child script in Yarn

I have a package.json that looks similar to this:

"scripts": {
    "dev": "cross-env BABEL_ENV=client webpack --config webpack/client.development.js && yarn dev:stub-server | cross-env BABEL_ENV=server babel-node src/server/server.js",
    "dev:stub-server": "./node_modules/.bin/robohydra ./stubs/robohydra-config.json -p 3100"
}

I added some logic in the code to change the way the dev:stub-server is configured depending on a command line argument. So, whenever I run the following I get what I expect:

yarn dev:stub-server --results=4
$ ./node_modules/.bin/robohydra ./stubs/robohydra-config.json -p 3100 -- --results=4

As you can see, the options are forwarded to the underlying script and everything works as expected.

My problem is that I cannot have the --results propagated from the yarn dev command to dev:stub-server in the correct position. The parent script runs dev:stub-server but the argument is forwarded to the underlying script at the end as follows:

yarn dev --results=2
$ cross-env BABEL_ENV=client webpack --config webpack/client.development.js && yarn dev:stub-server | cross-env BABEL_ENV=server babel-node src/server/server.js --results=2

Is there a way to make the above work as follows instead?

yarn dev --results=2
$ cross-env BABEL_ENV=client webpack --config webpack/client.development.js && yarn dev:stub-server --results=2 | cross-env BABEL_ENV=server babel-node src/server/server.js

Thanks in advance!

Solution

  • Yarn's run only supports appending your args to the end of the command chain, and at least as of date 2018-06-14, there isn't a way to override that.

    When I've needed this in the past, I've cooked up my own dev.js script that was called by my package.json, and pulled args out environment variables.