Fix early exit double-printing errors

lib/CliCommand.js

@@ -78,20 +78,18 @@ export default class CliCommand {
       message: 'Choose a release',
       choices: this.options.releaseData.releases.map(r => { return { title: r.name, value: r } })
     }])
-    if (release.branch || release.draft || release.prerelease) {
+    if (release && (release.branch || release.draft || release.prerelease)) {
       const { confirmed } = await this.getInput([{
         type: 'confirm',
         name: 'confirmed',
         message: 'Would you like to continue?',
         initial: false
       }], 'WARNING! YOU HAVE CHOSEN TO INSTALL A NON-STABLE VERSION WHICH IS NOT SUITABLE FOR PRODUCTION. PLEASE PROCEED WITH CAUTION.')
       console.log('\n')
-      if (!confirmed) {
-        console.log('\nGoodbye.')
-        this.cleanUp(new Error('User cancelled install'))
-      }
+      if(confirmed) return release.tag_name
     }
-    return release.tag_name
+    console.log('\nGoodbye.')
+    this.cleanUp(new Error('User cancelled install'))
   }
 
   async getInput (configs, message) {
@@ -122,5 +120,6 @@ export default class CliCommand {
     }
     console.log('Goodbye!')
     process.exitCode = error ? 1 : 0
+    process.exit()
   }
 }