fix(cli): creating project in current directory

closes vuejs#896

Author: kazupon

Diff for: packages/@vue/cli/lib/create.js

@@ -8,28 +8,44 @@ const clearConsole = require('./util/clearConsole')
 const { error, stopSpinner } = require('@vue/cli-shared-utils')
 
 async function create (projectName, options) {
-  const targetDir = path.resolve(process.cwd(), projectName)
+  const inCurrent = projectName === '.'
+  const name = inCurrent ? path.relative('../', process.cwd()) : projectName
+  const targetDir = path.resolve(projectName || '.')
+
   if (fs.existsSync(targetDir)) {
     if (options.force) {
       rimraf.sync(targetDir)
     } else {
       await clearConsole()
-      const { action } = await inquirer.prompt([
-        {
-          name: 'action',
-          type: 'list',
-          message: `Target directory ${chalk.cyan(targetDir)} already exists. Pick an action:`,
-          choices: [
-            { name: 'Overwrite', value: 'overwrite' },
-            { name: 'Merge', value: 'merge' },
-            { name: 'Cancel', value: false }
-          ]
+      if (inCurrent) {
+        const { ok } = await inquirer.prompt([
+          {
+            name: 'ok',
+            type: 'confirm',
+            message: `Generate project in current directory ${chalk.cyan(targetDir)} ?`
+          }
+        ])
+        if (!ok) {
+          return
+        }
+      } else {
+        const { action } = await inquirer.prompt([
+          {
+            name: 'action',
+            type: 'list',
+            message: `Target directory ${chalk.cyan(targetDir)} already exists. Pick an action:`,
+            choices: [
+              { name: 'Overwrite', value: 'overwrite' },
+              { name: 'Merge', value: 'merge' },
+              { name: 'Cancel', value: false }
+            ]
+          }
+        ])
+        if (!action) {
+          return
+        } else if (action === 'overwrite') {
+          rimraf.sync(targetDir)
         }
-      ])
-      if (!action) {
-        return
-      } else if (action === 'overwrite') {
-        rimraf.sync(targetDir)
       }
     }
   }
@@ -46,7 +62,7 @@ async function create (projectName, options) {
     'e2e'
   ].map(file => require(`./promptModules/${file}`))
 
-  const creator = new Creator(projectName, targetDir, promptModules)
+  const creator = new Creator(name, targetDir, promptModules)
   await creator.create(options)
 }