fix(workspaces): explicitly error in global mode

Also includes a preliminary refactor to consolidate workspace logic now
that every command that supports workspaces has it implemented.

PR-URL: https://github.com/npm/cli/pull/3417
Credit: @wraithgar
Close: #3417
Reviewed-by: @ruyadorno

1 files changed, 2 insertions, 5 deletions

diff --git a/lib/workspaces/arborist-cmd.js b/lib/workspaces/arborist-cmd.js
index 337e7f9d8..cb6b66b8c 100644
--- a/lib/workspaces/arborist-cmd.js
+++ b/lib/workspaces/arborist-cmd.js
@@ -3,7 +3,6 @@
 // be able to run a filtered Arborist.reify() at some point.
 
 const BaseCommand = require('../base-command.js')
-const getWorkspaces = require('./get-workspaces.js')
 class ArboristCmd extends BaseCommand {
   /* istanbul ignore next - see test/lib/load-all-commands.js */
   static get params () {
@@ -14,10 +13,8 @@ class ArboristCmd extends BaseCommand {
   }
 
   execWorkspaces (args, filters, cb) {
-    getWorkspaces(filters, { path: this.npm.localPrefix })
-      .then(workspaces => {
-        this.workspaces = [...workspaces.keys()]
-        this.workspacePaths = [...workspaces.values()]
+    this.setWorkspaces(filters)
+      .then(() => {
         this.exec(args, cb)
       })
       .catch(er => cb(er))