feat: add exec workspaces

Add workspaces support to `npm exec`
  - Refactored logic to read and filter workspaces into
  `lib/workspaces/get-workspaces.js`
  - Added location context message when entering interactive
  shell using `npm exec` (with no args)
  - Add ability to execute a package in the context of each
  configured workspace

Fixes: https://github.com/npm/statusboard/issues/288

PR-URL: https://github.com/npm/cli/pull/2886
Credit: @ruyadorno
Close: #2886
Reviewed-by: @wraithgar

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/workspaces/get-workspaces.js b/lib/workspaces/get-workspaces.js
new file mode 100644
index 000000000..64812d540
--- /dev/null
+++ b/lib/workspaces/get-workspaces.js
@@ -0,0 +1,33 @@
+const { resolve } = require('path')
+const mapWorkspaces = require('@npmcli/map-workspaces')
+const minimatch = require('minimatch')
+const rpj = require('read-package-json-fast')
+
+const getWorkspaces = async (filters, { path }) => {
+  const pkg = await rpj(resolve(path, 'package.json'))
+  const workspaces = await mapWorkspaces({ cwd: path, pkg })
+  const res = filters.length ? new Map() : workspaces
+
+  for (const filterArg of filters) {
+    for (const [workspaceName, workspacePath] of workspaces.entries()) {
+      if (filterArg === workspaceName
+        || resolve(path, filterArg) === workspacePath
+        || minimatch(workspacePath, `${resolve(path, filterArg)}/*`))
+        res.set(workspaceName, workspacePath)
+    }
+  }
+
+  if (!res.size) {
+    let msg = '!'
+    if (filters.length) {
+      msg = `:\n ${filters.reduce(
+        (res, filterArg) => `${res} --workspace=${filterArg}`, '')}`
+    }
+
+    throw new Error(`No workspaces found${msg}`)
+  }
+
+  return res
+}
+
+module.exports = getWorkspaces