diff --git a/lib/prepare.js b/lib/prepare.js
deleted file mode 100644
index 6ebb351df5..0000000000
--- a/lib/prepare.js
+++ /dev/null
@@ -1,352 +0,0 @@
-const path = require('path')
-const fs = require('fs-extra')
-const globby = require('globby')
-const createMarkdown = require('./markdown')
-const loadConfig = require('./util/loadConfig')
-const tempPath = path.resolve(__dirname, 'app/.temp')
-const {
-  encodePath,
-  inferTitle,
-  extractHeaders,
-  parseFrontmatter,
-  getGitLastUpdatedTimeStamp
-} = require('./util')
-
-fs.ensureDirSync(tempPath)
-
-const tempCache = new Map()
-async function writeTemp (file, content) {
-  // cache write to avoid hitting the dist if it didn't change
-  const cached = tempCache.get(file)
-  if (cached !== content) {
-    await fs.writeFile(path.join(tempPath, file), content)
-    tempCache.set(file, content)
-  }
-}
-
-async function writeEnhanceTemp (destName, srcPath) {
-  await writeTemp(
-    destName,
-    fs.existsSync(srcPath)
-      ? `export { default } from ${JSON.stringify(srcPath)}`
-      : `export default function () {}`
-  )
-}
-
-module.exports = async function prepare (sourceDir) {
-  // 1. load options
-  const options = await resolveOptions(sourceDir)
-
-  // 2. generate routes & user components registration code
-  const routesCode = await genRoutesFile(options)
-  const componentCode = await genComponentRegistrationFile(options)
-
-  await writeTemp('routes.js', [
-    componentCode,
-    routesCode
-  ].join('\n'))
-
-  // 3. generate siteData
-  const dataCode = `export const siteData = ${JSON.stringify(options.siteData, null, 2)}`
-  await writeTemp('siteData.js', dataCode)
-
-  // 4. handle user override
-  const overridePath = path.resolve(sourceDir, '.vuepress/override.styl')
-  const hasUserOverride = fs.existsSync(overridePath)
-  await writeTemp(`override.styl`, hasUserOverride ? `@import(${JSON.stringify(overridePath)})` : ``)
-
-  // 5. handle enhanceApp.js
-  const enhanceAppPath = path.resolve(sourceDir, '.vuepress/enhanceApp.js')
-  await writeEnhanceTemp('enhanceApp.js', enhanceAppPath)
-
-  // 6. handle the theme enhanceApp.js
-  await writeEnhanceTemp('themeEnhanceApp.js', options.themeEnhanceAppPath)
-
-  return options
-}
-
-async function resolveOptions (sourceDir) {
-  const vuepressDir = path.resolve(sourceDir, '.vuepress')
-  const siteConfig = loadConfig(vuepressDir)
-
-  // normalize head tag urls for base
-  const base = siteConfig.base || '/'
-  if (base !== '/' && siteConfig.head) {
-    siteConfig.head.forEach(tag => {
-      const attrs = tag[1]
-      if (attrs) {
-        for (const name in attrs) {
-          if (name === 'src' || name === 'href') {
-            const value = attrs[name]
-            if (value.charAt(0) === '/') {
-              attrs[name] = base + value.slice(1)
-            }
-          }
-        }
-      }
-    })
-  }
-
-  // resolve outDir
-  const outDir = siteConfig.dest
-    ? path.resolve(siteConfig.dest)
-    : path.resolve(sourceDir, '.vuepress/dist')
-
-  // resolve theme
-  const useDefaultTheme = (
-    !siteConfig.theme &&
-    !fs.existsSync(path.resolve(vuepressDir, 'theme'))
-  )
-  const defaultThemePath = path.resolve(__dirname, 'default-theme')
-  let themePath = null
-  let themeLayoutPath = null
-  let themeNotFoundPath = null
-  let themeEnhanceAppPath = null
-
-  if (useDefaultTheme) {
-    // use default theme
-    themePath = defaultThemePath
-    themeLayoutPath = path.resolve(defaultThemePath, 'Layout.vue')
-    themeNotFoundPath = path.resolve(defaultThemePath, 'NotFound.vue')
-  } else {
-    // resolve theme Layout
-    if (siteConfig.theme) {
-      // use external theme
-      try {
-        themeLayoutPath = require.resolve(`vuepress-theme-${siteConfig.theme}/Layout.vue`, {
-          paths: [
-            path.resolve(__dirname, '../node_modules'),
-            path.resolve(sourceDir)
-          ]
-        })
-        themePath = path.dirname(themeLayoutPath)
-      } catch (e) {
-        throw new Error(`[vuepress] Failed to load custom theme "${
-          siteConfig.theme
-        }". File vuepress-theme-${siteConfig.theme}/Layout.vue does not exist.`)
-      }
-    } else {
-      // use custom theme
-      themePath = path.resolve(vuepressDir, 'theme')
-      themeLayoutPath = path.resolve(themePath, 'Layout.vue')
-      if (!fs.existsSync(themeLayoutPath)) {
-        throw new Error(`[vuepress] Cannot resolve Layout.vue file in .vuepress/theme.`)
-      }
-    }
-
-    // resolve theme NotFound
-    themeNotFoundPath = path.resolve(themePath, 'NotFound.vue')
-    if (!fs.existsSync(themeNotFoundPath)) {
-      themeNotFoundPath = path.resolve(defaultThemePath, 'NotFound.vue')
-    }
-
-    // resolve theme enhanceApp
-    themeEnhanceAppPath = path.resolve(themePath, 'enhanceApp.js')
-    if (!fs.existsSync(themeEnhanceAppPath)) {
-      themeEnhanceAppPath = null
-    }
-  }
-
-  // resolve theme config
-  const themeConfig = siteConfig.themeConfig || {}
-
-  // resolve algolia
-  const isAlgoliaSearch = (
-    themeConfig.algolia ||
-    Object.keys(siteConfig.locales && themeConfig.locales || {})
-      .some(base => themeConfig.locales[base].algolia)
-  )
-
-  // resolve markdown
-  const markdown = createMarkdown(siteConfig)
-
-  // resolve pageFiles
-  const pageFiles = sort(await globby(['**/*.md', '!.vuepress', '!node_modules'], { cwd: sourceDir }))
-
-  // resolve lastUpdated
-  const shouldResolveLastUpdated = (
-    themeConfig.lastUpdated ||
-    Object.keys(siteConfig.locales && themeConfig.locales || {})
-      .some(base => themeConfig.locales[base].lastUpdated)
-  )
-
-  // resolve pagesData
-  const pagesData = await Promise.all(pageFiles.map(async (file) => {
-    const filepath = path.resolve(sourceDir, file)
-    const key = 'v-' + Math.random().toString(16).slice(2)
-    const data = {
-      key,
-      path: encodePath(fileToPath(file))
-    }
-
-    if (shouldResolveLastUpdated) {
-      data.lastUpdated = getGitLastUpdatedTimeStamp(filepath)
-    }
-
-    // extract yaml frontmatter
-    const content = await fs.readFile(filepath, 'utf-8')
-    const frontmatter = parseFrontmatter(content)
-    // infer title
-    const title = inferTitle(frontmatter)
-    if (title) {
-      data.title = title
-    }
-    const headers = extractHeaders(
-      frontmatter.content,
-      ['h2', 'h3'],
-      markdown
-    )
-    if (headers.length) {
-      data.headers = headers
-    }
-    if (Object.keys(frontmatter.data).length) {
-      data.frontmatter = frontmatter.data
-    }
-    if (frontmatter.excerpt) {
-      const { html } = markdown.render(frontmatter.excerpt)
-      data.excerpt = html
-    }
-    return data
-  }))
-
-  // resolve site data
-  const siteData = {
-    title: siteConfig.title || '',
-    description: siteConfig.description || '',
-    base,
-    pages: pagesData,
-    themeConfig,
-    locales: siteConfig.locales
-  }
-
-  const options = {
-    siteConfig,
-    siteData,
-    sourceDir,
-    outDir,
-    publicPath: base,
-    pageFiles,
-    pagesData,
-    themePath,
-    themeLayoutPath,
-    themeNotFoundPath,
-    themeEnhanceAppPath,
-    useDefaultTheme,
-    isAlgoliaSearch,
-    markdown
-  }
-
-  return options
-}
-
-async function genComponentRegistrationFile ({ sourceDir }) {
-  function genImport (file) {
-    const name = fileToComponentName(file)
-    const baseDir = path.resolve(sourceDir, '.vuepress/components')
-    const absolutePath = path.resolve(baseDir, file)
-    const code = `Vue.component(${JSON.stringify(name)}, () => import(${JSON.stringify(absolutePath)}))`
-    return code
-  }
-  const components = (await resolveComponents(sourceDir)) || []
-  return `import Vue from 'vue'\n` + components.map(genImport).join('\n')
-}
-
-const indexRE = /(^|.*\/)(index|readme)\.md$/i
-const extRE = /\.(vue|md)$/
-
-function fileToPath (file) {
-  if (isIndexFile(file)) {
-    // README.md -> /
-    // foo/README.md -> /foo/
-    return file.replace(indexRE, '/$1')
-  } else {
-    // foo.md -> /foo.html
-    // foo/bar.md -> /foo/bar.html
-    return `/${file.replace(extRE, '').replace(/\\/g, '/')}.html`
-  }
-}
-
-function fileToComponentName (file) {
-  let normalizedName = file
-    .replace(/\/|\\/g, '-')
-    .replace(extRE, '')
-  if (isIndexFile(file)) {
-    normalizedName = normalizedName.replace(/readme$/i, 'index')
-  }
-  const pagePrefix = /\.md$/.test(file) ? `page-` : ``
-  return `${pagePrefix}${normalizedName}`
-}
-
-function isIndexFile (file) {
-  return indexRE.test(file)
-}
-
-async function resolveComponents (sourceDir) {
-  const componentDir = path.resolve(sourceDir, '.vuepress/components')
-  if (!fs.existsSync(componentDir)) {
-    return
-  }
-  return sort(await globby(['**/*.vue'], { cwd: componentDir }))
-}
-
-async function genRoutesFile ({ siteData: { pages }, sourceDir, pageFiles }) {
-  function genRoute ({ path: pagePath, key: componentName }, index) {
-    const file = pageFiles[index]
-    const filePath = path.resolve(sourceDir, file)
-    let code = `
-  {
-    name: ${JSON.stringify(componentName)},
-    path: ${JSON.stringify(pagePath)},
-    component: ThemeLayout,
-    beforeEnter: (to, from, next) => {
-      import(${JSON.stringify(filePath)}).then(comp => {
-        Vue.component(${JSON.stringify(componentName)}, comp.default)
-        next()
-      })
-    }
-  }`
-
-    const dncodedPath = decodeURIComponent(pagePath)
-    if (dncodedPath !== pagePath) {
-      code += `,
-  {
-    path: ${JSON.stringify(dncodedPath)},
-    redirect: ${JSON.stringify(pagePath)}
-  }`
-    }
-
-    if (/\/$/.test(pagePath)) {
-      code += `,
-  {
-    path: ${JSON.stringify(pagePath + 'index.html')},
-    redirect: ${JSON.stringify(pagePath)}
-  }`
-    }
-
-    return code
-  }
-
-  const notFoundRoute = `,
-  {
-    path: '*',
-    component: ThemeNotFound
-  }`
-
-  return (
-    `import ThemeLayout from '@themeLayout'\n` +
-    `import ThemeNotFound from '@themeNotFound'\n` +
-    `import { injectMixins } from '@app/util'\n` +
-    `import rootMixins from '@app/root-mixins'\n\n` +
-    `injectMixins(ThemeLayout, rootMixins)\n` +
-    `injectMixins(ThemeNotFound, rootMixins)\n\n` +
-    `export const routes = [${pages.map(genRoute).join(',')}${notFoundRoute}\n]`
-  )
-}
-
-function sort (arr) {
-  return arr.sort((a, b) => {
-    if (a < b) return -1
-    if (a > b) return 1
-    return 0
-  })
-}
diff --git a/lib/prepare/codegen.js b/lib/prepare/codegen.js
new file mode 100644
index 0000000000..52e85355a2
--- /dev/null
+++ b/lib/prepare/codegen.js
@@ -0,0 +1,74 @@
+const path = require('path')
+const { fileToComponentName, resolveComponents } = require('./util')
+
+exports.genRoutesFile = async function ({
+  siteData: { pages },
+  sourceDir,
+  pageFiles
+}) {
+  function genRoute ({ path: pagePath, key: componentName }, index) {
+    const file = pageFiles[index]
+    const filePath = path.resolve(sourceDir, file)
+    let code = `
+  {
+    name: ${JSON.stringify(componentName)},
+    path: ${JSON.stringify(pagePath)},
+    component: ThemeLayout,
+    beforeEnter: (to, from, next) => {
+      import(${JSON.stringify(filePath)}).then(comp => {
+        Vue.component(${JSON.stringify(componentName)}, comp.default)
+        next()
+      })
+    }
+  }`
+
+    const dncodedPath = decodeURIComponent(pagePath)
+    if (dncodedPath !== pagePath) {
+      code += `,
+  {
+    path: ${JSON.stringify(dncodedPath)},
+    redirect: ${JSON.stringify(pagePath)}
+  }`
+    }
+
+    if (/\/$/.test(pagePath)) {
+      code += `,
+  {
+    path: ${JSON.stringify(pagePath + 'index.html')},
+    redirect: ${JSON.stringify(pagePath)}
+  }`
+    }
+
+    return code
+  }
+
+  const notFoundRoute = `,
+  {
+    path: '*',
+    component: ThemeNotFound
+  }`
+
+  return (
+    `import ThemeLayout from '@themeLayout'\n` +
+    `import ThemeNotFound from '@themeNotFound'\n` +
+    `import { injectMixins } from '@app/util'\n` +
+    `import rootMixins from '@app/root-mixins'\n\n` +
+    `injectMixins(ThemeLayout, rootMixins)\n` +
+    `injectMixins(ThemeNotFound, rootMixins)\n\n` +
+    `export const routes = [${pages.map(genRoute).join(',')}${notFoundRoute}\n]`
+  )
+}
+
+exports.genComponentRegistrationFile = async function ({ sourceDir }) {
+  function genImport (file) {
+    const name = fileToComponentName(file)
+    const baseDir = path.resolve(sourceDir, '.vuepress/components')
+    const absolutePath = path.resolve(baseDir, file)
+    const code = `Vue.component(${JSON.stringify(name)}, () => import(${JSON.stringify(absolutePath)}))`
+    return code
+  }
+
+  const components = (await resolveComponents(sourceDir)) || []
+  return `import Vue from 'vue'\n` + components.map(genImport).join('\n')
+}
+
diff --git a/lib/prepare/index.js b/lib/prepare/index.js
new file mode 100644
index 0000000000..b2a0a0b45f
--- /dev/null
+++ b/lib/prepare/index.js
@@ -0,0 +1,37 @@
+const path = require('path')
+const fs = require('fs-extra')
+const resolveOptions = require('./resolveOptions')
+const { genRoutesFile, genComponentRegistrationFile } = require('./codegen')
+const { writeTemp, writeEnhanceTemp } = require('./util')
+
+module.exports = async function prepare (sourceDir) {
+  // 1. load options
+  const options = await resolveOptions(sourceDir)
+
+  // 2. generate routes & user components registration code
+  const routesCode = await genRoutesFile(options)
+  const componentCode = await genComponentRegistrationFile(options)
+
+  await writeTemp('routes.js', [
+    componentCode,
+    routesCode
+  ].join('\n'))
+
+  // 3. generate siteData
+  const dataCode = `export const siteData = ${JSON.stringify(options.siteData, null, 2)}`
+  await writeTemp('siteData.js', dataCode)
+
+  // 4. handle user override
+  const overridePath = path.resolve(sourceDir, '.vuepress/override.styl')
+  const hasUserOverride = fs.existsSync(overridePath)
+  await writeTemp(`override.styl`, hasUserOverride ? `@import(${JSON.stringify(overridePath)})` : ``)
+
+  // 5. handle enhanceApp.js
+  const enhanceAppPath = path.resolve(sourceDir, '.vuepress/enhanceApp.js')
+  await writeEnhanceTemp('enhanceApp.js', enhanceAppPath)
+
+  // 6. handle the theme enhanceApp.js
+  await writeEnhanceTemp('themeEnhanceApp.js', options.themeEnhanceAppPath)
+
+  return options
+}
diff --git a/lib/util/loadConfig.js b/lib/prepare/loadConfig.js
similarity index 100%
rename from lib/util/loadConfig.js
rename to lib/prepare/loadConfig.js
diff --git a/lib/prepare/resolveOptions.js b/lib/prepare/resolveOptions.js
new file mode 100644
index 0000000000..76fa2fcc78
--- /dev/null
+++ b/lib/prepare/resolveOptions.js
@@ -0,0 +1,185 @@
+const fs = require('fs-extra')
+const path = require('path')
+const globby = require('globby')
+const createMarkdown = require('../markdown')
+const loadConfig = require('./loadConfig')
+const { encodePath, fileToPath, sort, getGitLastUpdatedTimeStamp } = require('./util')
+const {
+  inferTitle,
+  extractHeaders,
+  parseFrontmatter
+} = require('../util/index')
+
+module.exports = async function resolveOptions (sourceDir) {
+  const vuepressDir = path.resolve(sourceDir, '.vuepress')
+  const siteConfig = loadConfig(vuepressDir)
+
+  // normalize head tag urls for base
+  const base = siteConfig.base || '/'
+  if (base !== '/' && siteConfig.head) {
+    siteConfig.head.forEach(tag => {
+      const attrs = tag[1]
+      if (attrs) {
+        for (const name in attrs) {
+          if (name === 'src' || name === 'href') {
+            const value = attrs[name]
+            if (value.charAt(0) === '/') {
+              attrs[name] = base + value.slice(1)
+            }
+          }
+        }
+      }
+    })
+  }
+
+  // resolve outDir
+  const outDir = siteConfig.dest
+    ? path.resolve(siteConfig.dest)
+    : path.resolve(sourceDir, '.vuepress/dist')
+
+  // resolve theme
+  const useDefaultTheme = (
+    !siteConfig.theme &&
+    !fs.existsSync(path.resolve(vuepressDir, 'theme'))
+  )
+  const defaultThemePath = path.resolve(__dirname, '../default-theme')
+  let themePath = null
+  let themeLayoutPath = null
+  let themeNotFoundPath = null
+  let themeEnhanceAppPath = null
+
+  if (useDefaultTheme) {
+    // use default theme
+    themePath = defaultThemePath
+    themeLayoutPath = path.resolve(defaultThemePath, 'Layout.vue')
+    themeNotFoundPath = path.resolve(defaultThemePath, 'NotFound.vue')
+  } else {
+    // resolve theme Layout
+    if (siteConfig.theme) {
+      // use external theme
+      try {
+        themeLayoutPath = require.resolve(`vuepress-theme-${siteConfig.theme}/Layout.vue`, {
+          paths: [
+            path.resolve(__dirname, '../../node_modules'),
+            path.resolve(sourceDir)
+          ]
+        })
+        themePath = path.dirname(themeLayoutPath)
+      } catch (e) {
+        throw new Error(`[vuepress] Failed to load custom theme "${
+          siteConfig.theme
+        }". File vuepress-theme-${siteConfig.theme}/Layout.vue does not exist.`)
+      }
+    } else {
+      // use custom theme
+      themePath = path.resolve(vuepressDir, 'theme')
+      themeLayoutPath = path.resolve(themePath, 'Layout.vue')
+      if (!fs.existsSync(themeLayoutPath)) {
+        throw new Error(`[vuepress] Cannot resolve Layout.vue file in .vuepress/theme.`)
+      }
+    }
+
+    // resolve theme NotFound
+    themeNotFoundPath = path.resolve(themePath, 'NotFound.vue')
+    if (!fs.existsSync(themeNotFoundPath)) {
+      themeNotFoundPath = path.resolve(defaultThemePath, 'NotFound.vue')
+    }
+
+    // resolve theme enhanceApp
+    themeEnhanceAppPath = path.resolve(themePath, 'enhanceApp.js')
+    if (!fs.existsSync(themeEnhanceAppPath)) {
+      themeEnhanceAppPath = null
+    }
+  }
+
+  // resolve theme config
+  const themeConfig = siteConfig.themeConfig || {}
+
+  // resolve algolia
+  const isAlgoliaSearch = (
+    themeConfig.algolia ||
+    Object.keys(siteConfig.locales && themeConfig.locales || {})
+          .some(base => themeConfig.locales[base].algolia)
+  )
+
+  // resolve markdown
+  const markdown = createMarkdown(siteConfig)
+
+  // resolve pageFiles
+  const pageFiles = sort(await globby(['**/*.md', '!.vuepress', '!node_modules'], { cwd: sourceDir }))
+
+  // resolve lastUpdated
+  const shouldResolveLastUpdated = (
+    themeConfig.lastUpdated ||
+    Object.keys(siteConfig.locales && themeConfig.locales || {})
+          .some(base => themeConfig.locales[base].lastUpdated)
+  )
+
+  // resolve pagesData
+  const pagesData = await Promise.all(pageFiles.map(async (file) => {
+    const filepath = path.resolve(sourceDir, file)
+    const key = 'v-' + Math.random().toString(16).slice(2)
+    const data = {
+      key,
+      path: encodePath(fileToPath(file))
+    }
+
+    if (shouldResolveLastUpdated) {
+      data.lastUpdated = getGitLastUpdatedTimeStamp(filepath)
+    }
+
+    // extract yaml frontmatter
+    const content = await fs.readFile(filepath, 'utf-8')
+    const frontmatter = parseFrontmatter(content)
+    // infer title
+    const title = inferTitle(frontmatter)
+    if (title) {
+      data.title = title
+    }
+    const headers = extractHeaders(
+      frontmatter.content,
+      ['h2', 'h3'],
+      markdown
+    )
+    if (headers.length) {
+      data.headers = headers
+    }
+    if (Object.keys(frontmatter.data).length) {
+      data.frontmatter = frontmatter.data
+    }
+    if (frontmatter.excerpt) {
+      const { html } = markdown.render(frontmatter.excerpt)
+      data.excerpt = html
+    }
+    return data
+  }))
+
+  // resolve site data
+  const siteData = {
+    title: siteConfig.title || '',
+    description: siteConfig.description || '',
+    base,
+    pages: pagesData,
+    themeConfig,
+    locales: siteConfig.locales
+  }
+
+  const options = {
+    siteConfig,
+    siteData,
+    sourceDir,
+    outDir,
+    publicPath: base,
+    pageFiles,
+    pagesData,
+    themePath,
+    themeLayoutPath,
+    themeNotFoundPath,
+    themeEnhanceAppPath,
+    useDefaultTheme,
+    isAlgoliaSearch,
+    markdown
+  }
+
+  return options
+}
diff --git a/lib/prepare/util.js b/lib/prepare/util.js
new file mode 100644
index 0000000000..efa96cc9b7
--- /dev/null
+++ b/lib/prepare/util.js
@@ -0,0 +1,80 @@
+const path = require('path')
+const spawn = require('cross-spawn')
+const fs = require('fs-extra')
+const globby = require('globby')
+
+const tempPath = path.resolve(__dirname, '../app/.temp')
+fs.ensureDirSync(tempPath)
+
+const tempCache = new Map()
+exports.writeTemp = async function (file, content) {
+  // cache write to avoid hitting the dist if it didn't change
+  const cached = tempCache.get(file)
+  if (cached !== content) {
+    await fs.writeFile(path.join(tempPath, file), content)
+    tempCache.set(file, content)
+  }
+}
+
+exports.writeEnhanceTemp = async function (destName, srcPath) {
+  await exports.writeTemp(
+    destName,
+    fs.existsSync(srcPath)
+      ? `export { default } from ${JSON.stringify(srcPath)}`
+      : `export default function () {}`
+  )
+}
+
+const indexRE = /(^|.*\/)(index|readme)\.md$/i
+const extRE = /\.(vue|md)$/
+
+exports.fileToPath = function (file) {
+  if (exports.isIndexFile(file)) {
+    // README.md -> /
+    // foo/README.md -> /foo/
+    return file.replace(indexRE, '/$1')
+  } else {
+    // foo.md -> /foo.html
+    // foo/bar.md -> /foo/bar.html
+    return `/${file.replace(extRE, '').replace(/\\/g, '/')}.html`
+  }
+}
+
+exports.fileToComponentName = function (file) {
+  let normalizedName = file
+    .replace(/\/|\\/g, '-')
+    .replace(extRE, '')
+  if (exports.isIndexFile(file)) {
+    normalizedName = normalizedName.replace(/readme$/i, 'index')
+  }
+  const pagePrefix = /\.md$/.test(file) ? `page-` : ``
+  return `${pagePrefix}${normalizedName}`
+}
+
+exports.isIndexFile = function (file) {
+  return indexRE.test(file)
+}
+
+exports.resolveComponents = async function (sourceDir) {
+  const componentDir = path.resolve(sourceDir, '.vuepress/components')
+  if (!fs.existsSync(componentDir)) {
+    return
+  }
+  return exports.sort(await globby(['**/*.vue'], { cwd: componentDir }))
+}
+
+exports.sort = function (arr) {
+  return arr.sort((a, b) => {
+    if (a < b) return -1
+    if (a > b) return 1
+    return 0
+  })
+}
+
+exports.encodePath = function (userpath) {
+  return userpath.split('/').map(item => encodeURIComponent(item)).join('/')
+}
+
+exports.getGitLastUpdatedTimeStamp = function (filepath) {
+  return parseInt(spawn.sync('git', ['log', '-1', '--format=%ct', filepath]).stdout.toString('utf-8')) * 1000
+}
diff --git a/lib/util/index.js b/lib/util/index.js
index 4924ebe0ab..12caf0e7ac 100644
--- a/lib/util/index.js
+++ b/lib/util/index.js
@@ -1,11 +1,6 @@
-const spawn = require('cross-spawn')
 const parseHeaders = require('./parseHeaders')
 
-exports.encodePath = path => {
-  return path.split('/').map(item => encodeURIComponent(item)).join('/')
-}
-
-exports.normalizeHeadTag = tag => {
+exports.normalizeHeadTag = function (tag) {
   if (typeof tag === 'string') {
     tag = [tag]
   }
@@ -18,7 +13,7 @@ exports.normalizeHeadTag = tag => {
   }
 }
 
-exports.applyUserWebpackConfig = (userConfig, config, isServer) => {
+exports.applyUserWebpackConfig = function (userConfig, config, isServer) {
   const merge = require('webpack-merge')
   if (typeof userConfig === 'object') {
     return merge(config, userConfig)
@@ -32,7 +27,7 @@ exports.applyUserWebpackConfig = (userConfig, config, isServer) => {
   return config
 }
 
-exports.inferTitle = frontmatter => {
+exports.inferTitle = function (frontmatter) {
   if (frontmatter.data.home) {
     return 'Home'
   }
@@ -45,7 +40,7 @@ exports.inferTitle = frontmatter => {
   }
 }
 
-exports.parseFrontmatter = content => {
+exports.parseFrontmatter = function (content) {
   const matter = require('gray-matter')
   const toml = require('toml')
 
@@ -61,7 +56,7 @@ exports.parseFrontmatter = content => {
 const LRU = require('lru-cache')
 const cache = LRU({ max: 1000 })
 
-exports.extractHeaders = (content, include = [], md) => {
+exports.extractHeaders = function (content, include = [], md) {
   const key = content + include.join(',')
   const hit = cache.get(key)
   if (hit) {
@@ -86,7 +81,3 @@ exports.extractHeaders = (content, include = [], md) => {
   cache.set(key, res)
   return res
 }
-
-exports.getGitLastUpdatedTimeStamp = filepath => {
-  return parseInt(spawn.sync('git', ['log', '-1', '--format=%ct', filepath]).stdout.toString('utf-8')) * 1000
-}
diff --git a/test/prepare/fixtures/docs-custom-theme/.vuepress/config.js b/test/prepare/fixtures/docs-custom-theme/.vuepress/config.js
new file mode 100644
index 0000000000..a5f568cb6d
--- /dev/null
+++ b/test/prepare/fixtures/docs-custom-theme/.vuepress/config.js
@@ -0,0 +1,4 @@
+module.exports = {
+  title: 'Hello VuePress',
+  description: 'Just playing around'
+}
diff --git a/test/prepare/fixtures/docs-custom-theme/.vuepress/theme/Layout.vue b/test/prepare/fixtures/docs-custom-theme/.vuepress/theme/Layout.vue
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/prepare/fixtures/docs-custom-theme/README.md b/test/prepare/fixtures/docs-custom-theme/README.md
new file mode 100644
index 0000000000..fdb4d2b582
--- /dev/null
+++ b/test/prepare/fixtures/docs-custom-theme/README.md
@@ -0,0 +1 @@
+# Simple Docs
diff --git a/test/prepare/fixtures/docs-simple-config/.vuepress/config.js b/test/prepare/fixtures/docs-simple-config/.vuepress/config.js
new file mode 100644
index 0000000000..70f49c13b3
--- /dev/null
+++ b/test/prepare/fixtures/docs-simple-config/.vuepress/config.js
@@ -0,0 +1,9 @@
+module.exports = {
+  title: 'Hello VuePress',
+  description: 'Just playing around',
+  dest: 'vuepress',
+  base: 'vuepress',
+  head: [
+    ['link', { rel: 'icon', href: '/logo.png' }]
+  ]
+}
diff --git a/test/prepare/fixtures/docs-simple-config/README.md b/test/prepare/fixtures/docs-simple-config/README.md
new file mode 100644
index 0000000000..fdb4d2b582
--- /dev/null
+++ b/test/prepare/fixtures/docs-simple-config/README.md
@@ -0,0 +1 @@
+# Simple Docs
diff --git a/test/prepare/fixtures/docs-simple/README.md b/test/prepare/fixtures/docs-simple/README.md
new file mode 100644
index 0000000000..fdb4d2b582
--- /dev/null
+++ b/test/prepare/fixtures/docs-simple/README.md
@@ -0,0 +1 @@
+# Simple Docs
diff --git a/test/prepare/resolveOptions.spec.js b/test/prepare/resolveOptions.spec.js
new file mode 100644
index 0000000000..433c565214
--- /dev/null
+++ b/test/prepare/resolveOptions.spec.js
@@ -0,0 +1,95 @@
+import path from 'path'
+import resolveOptions from '@/prepare/resolveOptions.js'
+
+const DEFAULT_THEME_PATH = path.resolve(__dirname, '../../lib/default-theme')
+const DEFAULT_THEME_LAYOUT_PATH = path.resolve(DEFAULT_THEME_PATH, 'Layout.vue')
+const DEFAULT_THEME_NOT_FOOUND_PATH = path.resolve(DEFAULT_THEME_PATH, 'NotFound.vue')
+
+describe('prepare - resolveOptions', () => {
+  test('single file docs without config.', async () => {
+    const { docsDir } = getDocsPaths('docs-simple')
+    const options = await resolveOptions(docsDir)
+    const {
+      siteConfig,
+      siteData,
+      sourceDir,
+      outDir,
+      publicPath,
+      pageFiles,
+      pagesData,
+      themePath,
+      themeLayoutPath,
+      themeNotFoundPath,
+      themeEnhanceAppPath,
+      useDefaultTheme,
+      isAlgoliaSearch,
+      markdown
+    } = options
+    expect(siteConfig).toEqual({})
+    expect(siteData).toEqual({
+      title: '',
+      description: '',
+      base: '/',
+      pages: pagesData,
+      themeConfig: {},
+      locales: undefined
+    })
+    expect(sourceDir).toBe(docsDir)
+    expect(outDir).toBe(path.resolve(docsDir, '.vuepress/dist'))
+    expect(publicPath).toBe('/')
+    expect(pageFiles).toHaveLength(1)
+    expect(pageFiles[0]).toBe('README.md')
+    expect(themePath).toBe(DEFAULT_THEME_PATH)
+    expect(themeLayoutPath).toBe(DEFAULT_THEME_LAYOUT_PATH)
+    expect(themeNotFoundPath).toBe(DEFAULT_THEME_NOT_FOOUND_PATH)
+    expect(themeEnhanceAppPath).toBe(null)
+    expect(useDefaultTheme).toBe(true)
+    expect(isAlgoliaSearch).toBe(false)
+    expect(typeof markdown).toBe('object')
+  })
+
+  test('single file docs with config', async () => {
+    const { docsDir, configPath } = getDocsPaths('docs-simple-config')
+    const options = await resolveOptions(docsDir)
+    const {
+      siteConfig,
+      outDir,
+      publicPath
+    } = options
+    expect(siteConfig).toEqual(require(configPath))
+    expect(siteConfig.base).toBe('vuepress')
+    expect(siteConfig.dest).toBe('vuepress')
+    expect(outDir).toBe(path.resolve('vuepress'))
+    expect(publicPath).toBe('vuepress')
+  })
+
+  test('simple docs with custom theme', async () => {
+    const paths = getDocsPaths('docs-custom-theme')
+    const options = await resolveOptions(paths.docsDir)
+    const {
+      themePath,
+      themeLayoutPath,
+      themeNotFoundPath,
+      useDefaultTheme
+    } = options
+    expect(useDefaultTheme).toBe(false)
+    expect(themePath).toBe(paths.themePath)
+    expect(themeLayoutPath).toBe(paths.themeLayoutPath)
+    expect(themeNotFoundPath).toBe(DEFAULT_THEME_NOT_FOOUND_PATH) // fallbacks to default theme's NotFound component.
+  })
+})
+
+function getDocsPaths (name) {
+  const docsDir = path.join(__dirname, `fixtures/${name}`)
+  const configPath = path.join(docsDir, '.vuepress/config.js')
+  const themePath = path.join(docsDir, '.vuepress/theme')
+  const themeLayoutPath = path.join(themePath, 'Layout.vue')
+  const themeNotFoundPath = path.join(themePath, 'NotFound.vue')
+  return {
+    docsDir,
+    configPath,
+    themePath,
+    themeLayoutPath,
+    themeNotFoundPath
+  }
+}
diff --git a/test/prepare/util.spec.js b/test/prepare/util.spec.js
new file mode 100644
index 0000000000..ca8e1691a4
--- /dev/null
+++ b/test/prepare/util.spec.js
@@ -0,0 +1,37 @@
+import {
+  isIndexFile,
+  fileToPath
+} from '@/prepare/util.js'
+
+describe('prepare - util', () => {
+  test('isIndexFile', () => {
+    [
+      'README.md',
+      'readme.md',
+      'INDEX.md',
+      'index.md',
+      'foo/README.md',
+      'foo/index.md'
+    ].forEach(file => {
+      expect(isIndexFile(file)).toBe(true)
+    });
+    [
+      'foo/one.md',
+      'one.md'
+    ].forEach(file => {
+      expect(isIndexFile(file)).toBe(false)
+    })
+  })
+
+  test('fileToPath', () => {
+    const asserts = {
+      'README.md': '/',
+      'foo/README.md': '/foo/',
+      'foo.md': '/foo.html',
+      'foo/bar.md': '/foo/bar.html'
+    }
+    Object.keys(asserts).forEach(file => {
+      expect(fileToPath(file)).toBe(asserts[file])
+    })
+  })
+})