feat: determine if yarn is installed

.eslintrc

@@ -25,13 +25,15 @@
     ],
     "arrow-parens": ["error", "as-needed"],
     "arrow-body-style": "off",
+    "no-underscore-dangle":"off",
     "no-else-return": [
       "error",
       {
         "allowElseIf": true
       }
     ],
     "max-len": ["error", { "code": 200 }],
-    "no-param-reassign": "off"
+    "no-param-reassign": "off",
+    "no-return-assign":["error"]
   }
 }

lib/Creator.js

@@ -6,6 +6,7 @@ const { clearConsole } = require('./util/clearConsole')
 const { render } = require('./util/render')
 const writeFileTree = require('./util/writeFileTree')
 const { log } = require('./util/logger')
+const { hasYarn } = require('./util/hasYarn')
 
 module.exports = class Creator {
   constructor(name, context, promptModules) {
@@ -14,9 +15,9 @@ module.exports = class Creator {
     const { featurePrompt } = this.resolveIntroPrompts()
     this.featurePrompt = featurePrompt
     this.injectedPrompts = [] // prompts
+    this.outroPrompts = this.resolveOutroPrompts() // packageManager
 
     const promptAPI = new PromptModuleAPI(this)
-
     promptModules.forEach(m => m(promptAPI))
   }
 
@@ -29,18 +30,22 @@ module.exports = class Creator {
         cssPreprocessor: 'sass',
         eslintConfig: 'base',
         stylelintConfig: 'recessOrder',
-        name: 'demo'
+        name: 'demo',
+        packageManager: 'yarn'
       }
     } else {
       preset = await this.promptAndResolvePreset()
     }
     const file = await render('./template', Object.assign(preset, { name: this.name }))
     const finalFile = await this.extractFinalFiles(preset, file)
     await writeFileTree(this.context, finalFile)
-
+    const packageManager = (preset.packageManager || (hasYarn() ? 'yarn' : 'npm'))
     log()
     log(`🎉  Successfully created project ${chalk.yellow(this.name)}.`)
-    log(`👉  Get started with the following commands:\n\n${this.context === process.cwd() ? '' : chalk.cyan(` ${chalk.gray('$')} cd ${this.name}\n`)}`)
+    log(`👉  Get started with the following commands:\n\n
+    ${this.context === process.cwd() ? '' : chalk.cyan(` ${chalk.gray('$')} cd ${this.name}\n`)}
+    ${chalk.cyan(` ${chalk.gray('$')} ${packageManager === 'yarn' ? 'yarn' : 'npm install'}\n`)}
+    ${chalk.cyan(` ${chalk.gray('$')} ${packageManager === 'yarn' ? 'yarn dev' : 'npm run dev'}`)}`)
     log()
   }
 
@@ -60,7 +65,7 @@ module.exports = class Creator {
         return originalWhen(answers)
       }
     })
-    const prompts = [this.featurePrompt, ...this.injectedPrompts]
+    const prompts = [this.featurePrompt, ...this.injectedPrompts, ...this.outroPrompts]
     return prompts
   }
 
@@ -79,6 +84,31 @@ module.exports = class Creator {
     }
   }
 
+  // eslint-disable-next-line
+  resolveOutroPrompts() {
+    if (hasYarn()) {
+      const outroPrompts = [
+        {
+          name: 'packageManager',
+          type: 'list',
+          message: 'Pick the package manager to use when installing dependencies:',
+          choices: [
+            {
+              name: 'Use Yarn',
+              value: 'yarn',
+              short: 'Yarn'
+            },
+            {
+              name: 'Use NPM',
+              value: 'npm',
+              short: 'NPM'
+            }
+          ]
+        }
+      ]
+      return outroPrompts
+    }
+  }
   // eslint-disable-next-line
   async extractFinalFiles(preset, file) {
     // delete .eslintrc and .eslintignore files if the features not include eslint

lib/util/hasYarn.js

@@ -0,0 +1,13 @@
+const { execSync } = require('child_process')
+
+exports.hasYarn = () => {
+  if (process.env.WEBPACK_PAGE_CLI_TEST) {
+    return true
+  }
+  try {
+    execSync('yarnpkg --version', { stdio: 'ignore' })
+    return true
+  } catch (e) {
+    return false
+  }
+}