Lerna: Use lerna exec to run a command in the root scope

[rheaditi]

(question)
Is there a way to use lerna exec/run to run a specific script/command in the root scope?

Expected Behaviour

We already use something like lerna run --scope=a <script>, but we'd like to be able to use lerna to execute a root script from a package script. Given a structure like:

.
├── lerna.json
├── package-lock.json
├── package.json
├── packages
│   ├── a
│   └── b
└── ...

Is there a way that a script "prestart" in packages/a/package.json can use lerna to run a script "xyz" which is in root package.json.

Something like:

// package.json
"xyz": "do-something-in-root-scope"

// packages/a/package.json
"prestart": "npx lerna run --scope <root> xyz"

Current Behaviour

According to this comment, it's a bad idea to add the root as a managed package.

Unsure how to proceed. Any help would be appreciated! Thank you :)

lerna.json

{
  "packages": [
    "packages/*"
  ],
  "version": "0.0.0"
}

Context

Your Environment

| Executable | Version |
| ---: | :--- |
| lerna --version | 3.16.4 |
| npm --version | 6.10.2 |
| yarn --version | N/A |
| node --version | 12.8.1 |

| OS | Version |
| --- | --- |
| macOS Mojave | 10.14.5 |

[evocateur]

This seems more than sufficient for your use case:

    "prestart": "cd ../.. && npm run xyz"

[vivekbhagwat]

@evocateur I strongly disagree that this is sufficient, as it relies on assuming a directory structure and the point is to keep the scope. if lerna kept track of the root path, that would be more stable and useful. Please reopen this.

[evocateur]

it relies on assuming a directory structure

I mean, yes? Like, your packages don't have a habit of changing their location in the directory tree often, do they?

if lerna kept track of the root path

$LERNA_ROOT_PATH is available to lerna exec.