sending custom arguments to npm (yarn) scripts wit

Question

I have an issue when trying to pass arguments to an npm script with lerna.

I have a node script that I want to run inside each package in the workspace. lerna docs suggests the following:

{
    "scripts": {
      "my-script": "lerna exec -- node \\$LERNA_ROOT_PATH/scripts/my-script.js"
    }
}

so now, if I run in the root yarn run my-script it will run the script inside each package in the workspace.

Sometimes, I need to scope the execution to a specific package. So running this from command line obviously works: lerna exec --scope somepackage -- node \$LERNA_ROOT_PATH/scripts/create-common-scripts.js.

My question: how can I connect the npm script with the lerna scope argument. this is not working: yarn run my-script --scope somepackage, as it sets the argument to the end of the command: lerna exec -- node \\$LERNA_ROOT_PATH/scripts/my-script.js --scope somepackage.

Thanks!

Answer 1

When using Lerna commands are often nested. Meaning one command will call anther command, etc. For example the following command:

npm run release (in monorepo root) [1] > lerna run release [2] > npm run release (in package) [3] > release-it [4]

In a shell arguments can be passed to nested commands at runtime using a double dash (--). It marks the end of the parameter (option) list. Any parameter after the -- will be hoisted to the next command. This will work with commands nested multiple levels deep, all you have to do is add the number of -- to match the level of the command you want to pass them to.

With the previous example in mind, the following command:

$ npm run release -- --stream -- -- --dry-run --no-git.requireCleanWorkingDir

Will hoists the parameters to:

1. npm run release
2. lerna run release --stream
3. npm run release
4. release-it --dry-run --no-git.requireCleanWorkingDir