diff --git a/.eslintrc.js b/.eslintrc.js
index a694c834..0d87945d 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -6,6 +6,7 @@ module.exports = {
   ],
   rules: {
     indent: ['error', 2, { MemberExpression: 'off' }],
-    "no-undef": ["error"]
+    "no-undef": ["error"],
+    'operator-linebreak': ["error", "before"]
   }
 }
diff --git a/packages/@vuepress/core/lib/app/app.js b/packages/@vuepress/core/lib/app/app.js
index 9adb77c0..1adc33e3 100644
--- a/packages/@vuepress/core/lib/app/app.js
+++ b/packages/@vuepress/core/lib/app/app.js
@@ -21,8 +21,8 @@ if (module.hot) {
   module.hot.accept(VUEPRESS_TEMP_PATH + '/internal/siteData.js', () => {
     if (siteData.base !== prevBase) {
       window.alert(
-        `[vuepress] Site base has changed. ` +
-        `Please restart dev server to ensure correct asset paths.`
+        `[vuepress] Site base has changed. `
+        + `Please restart dev server to ensure correct asset paths.`
       )
     }
   })
diff --git a/packages/@vuepress/core/lib/dev.js b/packages/@vuepress/core/lib/dev.js
index 6c683815..c8051d39 100644
--- a/packages/@vuepress/core/lib/dev.js
+++ b/packages/@vuepress/core/lib/dev.js
@@ -101,8 +101,8 @@ async function prepareServer (sourceDir, cliOptions = {}, context) {
   const { host, displayHost } = await resolveHost(cliOptions.host || ctx.siteConfig.host)
 
   // debug in a running dev process.
-  process.stdin &&
-  process.stdin.on('data', chunk => {
+  process.stdin
+  && process.stdin.on('data', chunk => {
     const parsed = chunk.toString('utf-8').trim()
     if (parsed === '*') {
       console.log(Object.keys(ctx))
diff --git a/packages/@vuepress/core/lib/internal-plugins/frontmatterBlock/loader.js b/packages/@vuepress/core/lib/internal-plugins/frontmatterBlock/loader.js
index bb29bece..c36c6fd3 100644
--- a/packages/@vuepress/core/lib/internal-plugins/frontmatterBlock/loader.js
+++ b/packages/@vuepress/core/lib/internal-plugins/frontmatterBlock/loader.js
@@ -12,11 +12,11 @@ module.exports = function (source, map) {
     const cached = cache.get(file)
     const parsed = parseStrippedFrontmatter(source)
 
-    if (cached &&
-      cached.data &&
-      parsed &&
-      parsed.data &&
-      JSON.stringify(cached.data) !== JSON.stringify(parsed.data)
+    if (cached
+      && cached.data
+      && parsed
+      && parsed.data
+      && JSON.stringify(cached.data) !== JSON.stringify(parsed.data)
     ) {
       frontmatterEmitter.emit('update')
     }
diff --git a/packages/@vuepress/core/lib/plugin-api/index.js b/packages/@vuepress/core/lib/plugin-api/index.js
index 69649f80..83639fb5 100644
--- a/packages/@vuepress/core/lib/plugin-api/index.js
+++ b/packages/@vuepress/core/lib/plugin-api/index.js
@@ -169,8 +169,8 @@ module.exports = class PluginAPI {
       this.options[option.name].add(pluginName, value)
     } else if (value !== undefined) {
       logger.warn(
-        `${chalk.gray(pluginName)} ` +
-        `Invalid value for "option" ${chalk.cyan(option.name)}: ${warnMsg}`
+        `${chalk.gray(pluginName)} `
+        + `Invalid value for "option" ${chalk.cyan(option.name)}: ${warnMsg}`
       )
     }
     return this
diff --git a/packages/@vuepress/core/lib/plugin-api/override/EnhanceAppFilesOption.js b/packages/@vuepress/core/lib/plugin-api/override/EnhanceAppFilesOption.js
index d9446d5c..c109c130 100644
--- a/packages/@vuepress/core/lib/plugin-api/override/EnhanceAppFilesOption.js
+++ b/packages/@vuepress/core/lib/plugin-api/override/EnhanceAppFilesOption.js
@@ -67,8 +67,8 @@ module.exports = class EnhanceAppFilesOption extends AsyncOption {
           }
         } else {
           logger.developer(
-            chalk.gray(`[${pluginName}] `) +
-            `${chalk.cyan(enhanceAppFile)} Not Found.`
+            chalk.gray(`[${pluginName}] `)
+            + `${chalk.cyan(enhanceAppFile)} Not Found.`
           )
         }
       }
diff --git a/packages/@vuepress/core/lib/plugin-api/util.js b/packages/@vuepress/core/lib/plugin-api/util.js
index bf40a15c..706da428 100644
--- a/packages/@vuepress/core/lib/plugin-api/util.js
+++ b/packages/@vuepress/core/lib/plugin-api/util.js
@@ -26,8 +26,8 @@ exports.flattenPlugin = function (
   if (!valid) {
     if (pluginOptions !== undefined) {
       logger.warn(
-        `[${chalk.gray(shortcut)}] ` +
-        `Invalid value for "pluginOptions" ${chalk.cyan(name)}: ${warnMsg}`
+        `[${chalk.gray(shortcut)}] `
+        + `Invalid value for "pluginOptions" ${chalk.cyan(name)}: ${warnMsg}`
       )
     }
     pluginOptions = {}
@@ -69,8 +69,8 @@ exports.normalizePluginsConfig = function (pluginsConfig) {
   if (!valid) {
     if (pluginsConfig !== undefined) {
       logger.warn(
-        `[${chalk.gray('config')}] ` +
-        `Invalid value for "plugin" field : ${warnMsg}`
+        `[${chalk.gray('config')}] `
+        + `Invalid value for "plugin" field : ${warnMsg}`
       )
     }
     pluginsConfig = []
diff --git a/packages/@vuepress/core/lib/prepare/AppContext.js b/packages/@vuepress/core/lib/prepare/AppContext.js
index c1176a15..09aee105 100644
--- a/packages/@vuepress/core/lib/prepare/AppContext.js
+++ b/packages/@vuepress/core/lib/prepare/AppContext.js
@@ -130,8 +130,8 @@ module.exports = class AppContext {
     const siteConfig = this.siteConfig
 
     const shouldUseLastUpdated = (
-      themeConfig.lastUpdated ||
-      Object.keys(siteConfig.locales && themeConfig.locales || {})
+      themeConfig.lastUpdated
+      || Object.keys(siteConfig.locales && themeConfig.locales || {})
         .some(base => themeConfig.locales[base].lastUpdated)
     )
 
diff --git a/packages/@vuepress/core/lib/prepare/CacheLoader.js b/packages/@vuepress/core/lib/prepare/CacheLoader.js
index 7b611a3a..7d102914 100644
--- a/packages/@vuepress/core/lib/prepare/CacheLoader.js
+++ b/packages/@vuepress/core/lib/prepare/CacheLoader.js
@@ -38,19 +38,19 @@ exports.getCacheLoaderOptions = function (siteConfig, cliOptions, cwd, isProd) {
         siteConfig.markdown
           ? JSON.stringify(siteConfig.markdown)
           : ''
-      ) +
-      (
+      )
+      + (
         siteConfig.markdown && siteConfig.markdown.extendMarkdown
           ? siteConfig.markdown.extendMarkdown.toString()
           : ''
-      ) +
-      (
+      )
+      + (
         siteConfig.extendMarkdown
           ? siteConfig.extendMarkdown.toString()
           : ''
-      ) +
-      (siteConfig.chainWebpack || '').toString() +
-      (siteConfig.configureWebpack || '').toString()
+      )
+      + (siteConfig.chainWebpack || '').toString()
+      + (siteConfig.configureWebpack || '').toString()
     )
   })
 
diff --git a/packages/@vuepress/core/lib/prepare/ClientComputedMixin.js b/packages/@vuepress/core/lib/prepare/ClientComputedMixin.js
index 2e99ba4c..dbe8a3f7 100644
--- a/packages/@vuepress/core/lib/prepare/ClientComputedMixin.js
+++ b/packages/@vuepress/core/lib/prepare/ClientComputedMixin.js
@@ -74,8 +74,8 @@ module.exports = siteData => {
 
       const siteTitle = this.$siteTitle
       const selfTitle = page.frontmatter.home ? null : (
-        page.frontmatter.title || // explicit title
-        page.title // inferred title
+        page.frontmatter.title // explicit title
+        || page.title // inferred title
       )
       return siteTitle
         ? selfTitle
diff --git a/packages/@vuepress/core/lib/prepare/loadTheme.js b/packages/@vuepress/core/lib/prepare/loadTheme.js
index dcede9eb..43056f73 100644
--- a/packages/@vuepress/core/lib/prepare/loadTheme.js
+++ b/packages/@vuepress/core/lib/prepare/loadTheme.js
@@ -34,10 +34,10 @@ module.exports = async function loadTheme (ctx) {
   const themeResolver = getThemeResolver()
 
   const localThemePath = path.resolve(vuepressDir, 'theme')
-  const useLocalTheme =
-    !fs.existsSync(theme) &&
-    fs.existsSync(localThemePath) &&
-    (fs.readdirSync(localThemePath)).length > 0
+  const useLocalTheme
+    = !fs.existsSync(theme)
+    && fs.existsSync(localThemePath)
+    && (fs.readdirSync(localThemePath)).length > 0
 
   let themePath = null         // Mandatory
   let themeEntryFile = null    // Optional
@@ -119,8 +119,8 @@ module.exports = async function loadTheme (ctx) {
   const readdirSync = dir => fs.existsSync(dir) && fs.readdirSync(dir) || []
 
   // built-in named layout or not.
-  const isInternal = componentName => componentName === 'Layout' ||
-    componentName === 'NotFound'
+  const isInternal = componentName => componentName === 'Layout'
+    || componentName === 'NotFound'
 
   const layoutComponentMap = layoutDirs
     .map(
diff --git a/packages/@vuepress/core/lib/webpack/DevLogPlugin.js b/packages/@vuepress/core/lib/webpack/DevLogPlugin.js
index 15a610d2..b51927e6 100644
--- a/packages/@vuepress/core/lib/webpack/DevLogPlugin.js
+++ b/packages/@vuepress/core/lib/webpack/DevLogPlugin.js
@@ -25,9 +25,9 @@ module.exports = class DevLogPlugin {
       const displayUrl = `http://${displayHost}:${port}${publicPath}`
 
       logger.success(
-        `${chalk.gray(`[${time}]`)} Build ${chalk.italic(stats.hash.slice(0, 6))} ` +
-        `finished in ${stats.endTime - stats.startTime} ms! ` +
-        (
+        `${chalk.gray(`[${time}]`)} Build ${chalk.italic(stats.hash.slice(0, 6))} `
+        + `finished in ${stats.endTime - stats.startTime} ms! `
+        + (
           isFirst
             ? ''
             : `${chalk.gray(`(${displayUrl})`)}`
diff --git a/packages/@vuepress/markdown-loader/index.js b/packages/@vuepress/markdown-loader/index.js
index 2043fc9d..8e53a7e2 100644
--- a/packages/@vuepress/markdown-loader/index.js
+++ b/packages/@vuepress/markdown-loader/index.js
@@ -49,9 +49,9 @@ module.exports = function (src) {
     // returned component, changes in frontmatter do not trigger proper updates
     const cachedData = devCache.get(file)
     if (cachedData && (
-      cachedData.inferredTitle !== inferredTitle ||
-      JSON.stringify(cachedData.frontmatterData) !== JSON.stringify(frontmatter.data) ||
-      headersChanged(cachedData.headers, headers)
+      cachedData.inferredTitle !== inferredTitle
+      || JSON.stringify(cachedData.frontmatterData) !== JSON.stringify(frontmatter.data)
+      || headersChanged(cachedData.headers, headers)
     )) {
       // frontmatter changed... need to do a full reload
       module.exports.frontmatterEmitter.emit('update')
@@ -91,19 +91,19 @@ module.exports = function (src) {
     if (!fs.existsSync(file) && (!altfile || !fs.existsSync(altfile))) {
       this.emitWarning(
         new Error(
-          `\nFile for relative link "${link}" does not exist.\n` +
-          `(Resolved file: ${file})\n`
+          `\nFile for relative link "${link}" does not exist.\n`
+          + `(Resolved file: ${file})\n`
         )
       )
     }
   })
 
   const res = (
-    `<template>\n` +
-      `<ContentSlotsDistributor :slot-key="$parent.slotKey">${html}</ContentSlotsDistributor>\n` +
-    `</template>\n` +
-    (hoistedTags || []).join('\n') +
-    `\n${dataBlockString}\n`
+    `<template>\n`
+      + `<ContentSlotsDistributor :slot-key="$parent.slotKey">${html}</ContentSlotsDistributor>\n`
+    + `</template>\n`
+    + (hoistedTags || []).join('\n')
+    + `\n${dataBlockString}\n`
   )
   cache.set(key, res)
   return res
@@ -112,8 +112,8 @@ module.exports = function (src) {
 function headersChanged (a, b) {
   if (a.length !== b.length) return true
   return a.some((h, i) => (
-    h.title !== b[i].title ||
-    h.level !== b[i].level
+    h.title !== b[i].title
+    || h.level !== b[i].level
   ))
 }
 
diff --git a/packages/@vuepress/markdown/lib/highlightLines.js b/packages/@vuepress/markdown/lib/highlightLines.js
index dd833432..c98dcc8e 100644
--- a/packages/@vuepress/markdown/lib/highlightLines.js
+++ b/packages/@vuepress/markdown/lib/highlightLines.js
@@ -41,8 +41,8 @@ module.exports = md => {
       return '<br>'
     }).join('')
 
-    const highlightLinesWrapperCode =
-      `<div class="highlight-lines">${highlightLinesCode}</div>`
+    const highlightLinesWrapperCode
+      = `<div class="highlight-lines">${highlightLinesCode}</div>`
 
     return highlightLinesWrapperCode + code
   }
diff --git a/packages/@vuepress/markdown/lib/lineNumbers.js b/packages/@vuepress/markdown/lib/lineNumbers.js
index bc95d2b0..6ee2f431 100644
--- a/packages/@vuepress/markdown/lib/lineNumbers.js
+++ b/packages/@vuepress/markdown/lib/lineNumbers.js
@@ -14,8 +14,8 @@ module.exports = md => {
     const lineNumbersCode = [...Array(lines.length - 1)]
       .map((line, index) => `<span class="line-number">${index + 1}</span><br>`).join('')
 
-    const lineNumbersWrapperCode =
-      `<div class="line-numbers-wrapper">${lineNumbersCode}</div>`
+    const lineNumbersWrapperCode
+      = `<div class="line-numbers-wrapper">${lineNumbersCode}</div>`
 
     const finalCode = rawCode
       .replace('<!--beforeend-->', `${lineNumbersWrapperCode}<!--beforeend-->`)
diff --git a/packages/@vuepress/markdown/lib/preWrapper.js b/packages/@vuepress/markdown/lib/preWrapper.js
index 8f1b1d73..35f7ed77 100644
--- a/packages/@vuepress/markdown/lib/preWrapper.js
+++ b/packages/@vuepress/markdown/lib/preWrapper.js
@@ -13,7 +13,7 @@ module.exports = md => {
     const [tokens, idx] = args
     const token = tokens[idx]
     const rawCode = fence(...args)
-    return `<!--beforebegin--><div class="language-${token.info.trim()} extra-class">` +
-    `<!--afterbegin-->${rawCode}<!--beforeend--></div><!--afterend-->`
+    return `<!--beforebegin--><div class="language-${token.info.trim()} extra-class">`
+    + `<!--afterbegin-->${rawCode}<!--beforeend--></div><!--afterend-->`
   }
 }
diff --git a/packages/@vuepress/plugin-active-header-links/clientRootMixin.js b/packages/@vuepress/plugin-active-header-links/clientRootMixin.js
index 7c6ec7b8..20ec55e6 100644
--- a/packages/@vuepress/plugin-active-header-links/clientRootMixin.js
+++ b/packages/@vuepress/plugin-active-header-links/clientRootMixin.js
@@ -27,9 +27,9 @@ export default {
         const anchor = anchors[i]
         const nextAnchor = anchors[i + 1]
 
-        const isActive = i === 0 && scrollTop === 0 ||
-          (scrollTop >= anchor.parentElement.offsetTop + 10 &&
-            (!nextAnchor || scrollTop < nextAnchor.parentElement.offsetTop - 10))
+        const isActive = i === 0 && scrollTop === 0
+          || (scrollTop >= anchor.parentElement.offsetTop + 10
+            && (!nextAnchor || scrollTop < nextAnchor.parentElement.offsetTop - 10))
 
         if (isActive && decodeURIComponent(this.$route.hash) !== decodeURIComponent(anchor.hash)) {
           this.$vuepress.$set('disableScrollBehavior', true)
diff --git a/packages/@vuepress/plugin-back-to-top/BackToTop.vue b/packages/@vuepress/plugin-back-to-top/BackToTop.vue
index ff7a7577..2ec371de 100644
--- a/packages/@vuepress/plugin-back-to-top/BackToTop.vue
+++ b/packages/@vuepress/plugin-back-to-top/BackToTop.vue
@@ -40,9 +40,9 @@ export default {
 
   methods: {
     getScrollTop () {
-      return window.pageYOffset ||
-        document.documentElement.scrollTop ||
-        document.body.scrollTop || 0
+      return window.pageYOffset
+        || document.documentElement.scrollTop
+        || document.body.scrollTop || 0
     },
 
     scrollToTop () {
diff --git a/packages/@vuepress/plugin-pwa/lib/enhanceAppFile.js b/packages/@vuepress/plugin-pwa/lib/enhanceAppFile.js
index 44e0f98f..3054f3d1 100644
--- a/packages/@vuepress/plugin-pwa/lib/enhanceAppFile.js
+++ b/packages/@vuepress/plugin-pwa/lib/enhanceAppFile.js
@@ -12,9 +12,9 @@ if (SW_UPDATE_POPUP) {
 export default ({ router, isServer }) => {
   // Register service worker
   router.onReady(() => {
-    if (process.env.NODE_ENV === 'production' &&
-      !isServer &&
-      SW_ENABLED) {
+    if (process.env.NODE_ENV === 'production'
+      && !isServer
+      && SW_ENABLED) {
       register(`${SW_BASE_URL}service-worker.js`, {
         ready () {
           console.log('[vuepress:sw] Service worker is active.')
diff --git a/packages/@vuepress/plugin-search/SearchBox.vue b/packages/@vuepress/plugin-search/SearchBox.vue
index 74e69610..6fbbd70b 100644
--- a/packages/@vuepress/plugin-search/SearchBox.vue
+++ b/packages/@vuepress/plugin-search/SearchBox.vue
@@ -49,9 +49,9 @@ export default {
   computed: {
     showSuggestions () {
       return (
-        this.focused &&
-        this.suggestions &&
-        this.suggestions.length
+        this.focused
+        && this.suggestions
+        && this.suggestions.length
       )
     },
 
@@ -65,8 +65,8 @@ export default {
       const max = SEARCH_MAX_SUGGESTIONS
       const localePath = this.$localePath
       const matches = item => (
-        item.title &&
-        item.title.toLowerCase().indexOf(query) > -1
+        item.title
+        && item.title.toLowerCase().indexOf(query) > -1
       )
       const res = []
       for (let i = 0; i < pages.length; i++) {
diff --git a/packages/@vuepress/shared-utils/scripts/update-index.js b/packages/@vuepress/shared-utils/scripts/update-index.js
index 03d23c8c..a5558b43 100644
--- a/packages/@vuepress/shared-utils/scripts/update-index.js
+++ b/packages/@vuepress/shared-utils/scripts/update-index.js
@@ -18,17 +18,17 @@ const EXPORTED_MODULES = [
   ['hash-sum', 'hash']
 ]
 
-const code =
-  [
+const code
+  = [
     ...modules.map(v => getImport(v, `./${v}`)),
     ...EXPORTED_MODULES.map(v => Array.isArray(v) ? getImport(v[1], v[0]) : getImport(v, v))
-  ].join('\n') +
-  `\n\nexport {\n` +
-  [
+  ].join('\n')
+  + `\n\nexport {\n`
+  + [
     ...modules,
     ...EXPORTED_MODULES.map(v => Array.isArray(v) ? v[1] : v)
-  ].map(v => `  ${v},`).join('\n') +
-  '\n}'
+  ].map(v => `  ${v},`).join('\n')
+  + '\n}'
 
 fs.writeFileSync(target, code, 'utf-8')
 
diff --git a/packages/@vuepress/theme-default/components/Navbar.vue b/packages/@vuepress/theme-default/components/Navbar.vue
index 8298d76c..86565a03 100644
--- a/packages/@vuepress/theme-default/components/Navbar.vue
+++ b/packages/@vuepress/theme-default/components/Navbar.vue
@@ -58,8 +58,8 @@ export default {
       if (document.documentElement.clientWidth < MOBILE_DESKTOP_BREAKPOINT) {
         this.linksWrapMaxWidth = null
       } else {
-        this.linksWrapMaxWidth = this.$el.offsetWidth - NAVBAR_VERTICAL_PADDING -
-          (this.$refs.siteName && this.$refs.siteName.offsetWidth || 0)
+        this.linksWrapMaxWidth = this.$el.offsetWidth - NAVBAR_VERTICAL_PADDING
+          - (this.$refs.siteName && this.$refs.siteName.offsetWidth || 0)
       }
     }
     handleLinksWrapWidth()
diff --git a/packages/@vuepress/theme-default/components/Page.vue b/packages/@vuepress/theme-default/components/Page.vue
index d1d0649e..55710db3 100644
--- a/packages/@vuepress/theme-default/components/Page.vue
+++ b/packages/@vuepress/theme-default/components/Page.vue
@@ -129,9 +129,9 @@ export default {
 
     editLinkText () {
       return (
-        this.$themeLocaleConfig.editLinkText ||
-        this.$site.themeConfig.editLinkText ||
-        `Edit this page`
+        this.$themeLocaleConfig.editLinkText
+        || this.$site.themeConfig.editLinkText
+        || `Edit this page`
       )
     }
   },
@@ -144,12 +144,12 @@ export default {
           ? docsRepo
           : repo
         return (
-          base.replace(endingSlashRE, '') +
-           `/src` +
-           `/${docsBranch}` +
-           (docsDir ? '/' + docsDir.replace(endingSlashRE, '') : '') +
-           path +
-           `?mode=edit&spa=0&at=${docsBranch}&fileviewer=file-view-default`
+          base.replace(endingSlashRE, '')
+           + `/src`
+           + `/${docsBranch}`
+           + (docsDir ? '/' + docsDir.replace(endingSlashRE, '') : '')
+           + path
+           + `?mode=edit&spa=0&at=${docsBranch}&fileviewer=file-view-default`
         )
       }
 
@@ -158,10 +158,10 @@ export default {
         : `https://github.com/${docsRepo}`
 
       return (
-        base.replace(endingSlashRE, '') +
-        `/edit/${docsBranch}` +
-        (docsDir ? '/' + docsDir.replace(endingSlashRE, '') : '') +
-        path
+        base.replace(endingSlashRE, '')
+        + `/edit/${docsBranch}`
+        + (docsDir ? '/' + docsDir.replace(endingSlashRE, '') : '')
+        + path
       )
     }
   }
diff --git a/packages/@vuepress/theme-default/components/SidebarLink.vue b/packages/@vuepress/theme-default/components/SidebarLink.vue
index 6a45295c..7d128b4a 100644
--- a/packages/@vuepress/theme-default/components/SidebarLink.vue
+++ b/packages/@vuepress/theme-default/components/SidebarLink.vue
@@ -30,15 +30,15 @@ export default {
       : selfActive
     const link = renderLink(h, item.path, item.title || item.path, active)
 
-    const configDepth = $page.frontmatter.sidebarDepth ||
-      sidebarDepth ||
-      $themeLocaleConfig.sidebarDepth ||
-      $themeConfig.sidebarDepth
+    const configDepth = $page.frontmatter.sidebarDepth
+      || sidebarDepth
+      || $themeLocaleConfig.sidebarDepth
+      || $themeConfig.sidebarDepth
 
     const maxDepth = configDepth == null ? 1 : configDepth
 
-    const displayAllHeaders = $themeLocaleConfig.displayAllHeaders ||
-      $themeConfig.displayAllHeaders
+    const displayAllHeaders = $themeLocaleConfig.displayAllHeaders
+      || $themeConfig.displayAllHeaders
 
     if (item.type === 'auto') {
       return [link, renderChildren(h, item.children, item.basePath, $route, maxDepth)]
diff --git a/packages/@vuepress/theme-default/index.js b/packages/@vuepress/theme-default/index.js
index dd28d69b..3cafe568 100644
--- a/packages/@vuepress/theme-default/index.js
+++ b/packages/@vuepress/theme-default/index.js
@@ -6,8 +6,8 @@ module.exports = (options, ctx) => ({
     const { themeConfig, siteConfig } = ctx
     // resolve algolia
     const isAlgoliaSearch = (
-      themeConfig.algolia ||
-      Object.keys(siteConfig.locales && themeConfig.locales || {})
+      themeConfig.algolia
+      || Object.keys(siteConfig.locales && themeConfig.locales || {})
         .some(base => themeConfig.locales[base].algolia)
     )
     return {
diff --git a/packages/@vuepress/theme-default/layouts/Layout.vue b/packages/@vuepress/theme-default/layouts/Layout.vue
index de6a0f60..4803dfd7 100644
--- a/packages/@vuepress/theme-default/layouts/Layout.vue
+++ b/packages/@vuepress/theme-default/layouts/Layout.vue
@@ -68,25 +68,25 @@ export default {
       const { themeConfig } = this.$site
       const { frontmatter } = this.$page
       if (
-        frontmatter.navbar === false ||
-        themeConfig.navbar === false) {
+        frontmatter.navbar === false
+        || themeConfig.navbar === false) {
         return false
       }
       return (
-        this.$title ||
-        themeConfig.logo ||
-        themeConfig.repo ||
-        themeConfig.nav ||
-        this.$themeLocaleConfig.nav
+        this.$title
+        || themeConfig.logo
+        || themeConfig.repo
+        || themeConfig.nav
+        || this.$themeLocaleConfig.nav
       )
     },
 
     shouldShowSidebar () {
       const { frontmatter } = this.$page
       return (
-        !frontmatter.home &&
-        frontmatter.sidebar !== false &&
-        this.sidebarItems.length
+        !frontmatter.home
+        && frontmatter.sidebar !== false
+        && this.sidebarItems.length
       )
     },
 
diff --git a/packages/@vuepress/theme-vue/components/CarbonAds.vue b/packages/@vuepress/theme-vue/components/CarbonAds.vue
index 9f413705..886e857a 100644
--- a/packages/@vuepress/theme-vue/components/CarbonAds.vue
+++ b/packages/@vuepress/theme-vue/components/CarbonAds.vue
@@ -9,11 +9,11 @@ export default {
   watch: {
     '$route' (to, from) {
       if (
-        to.path !== from.path &&
+        to.path !== from.path
         // Only reload if the ad has been loaded
         // otherwise it's possible that the script is appended but
         // the ads are not loaded yet. This would result in duplicated ads.
-        this.$el.querySelector('#carbonads')
+        && this.$el.querySelector('#carbonads')
       ) {
         this.$el.innerHTML = ''
         this.load()
diff --git a/packages/vuepress/lib/checkEnv.js b/packages/vuepress/lib/checkEnv.js
index 59020ae2..04a57d19 100644
--- a/packages/vuepress/lib/checkEnv.js
+++ b/packages/vuepress/lib/checkEnv.js
@@ -15,9 +15,9 @@ module.exports = function checkEnv (pkg) {
 
   if (!semver.satisfies(process.version, requiredVersion)) {
     console.log(chalk.red(
-      `\n[vuepress] minimum Node version not met:` +
-      `\nYou are using Node ${process.version}, but VuePress ` +
-      `requires Node ${requiredVersion}.\nPlease upgrade your Node version.\n`
+      `\n[vuepress] minimum Node version not met:`
+      + `\nYou are using Node ${process.version}, but VuePress `
+      + `requires Node ${requiredVersion}.\nPlease upgrade your Node version.\n`
     ))
     process.exit(1)
   }
diff --git a/packages/vuepress/lib/handleUnknownCommand.js b/packages/vuepress/lib/handleUnknownCommand.js
index 6a127880..937f70dd 100644
--- a/packages/vuepress/lib/handleUnknownCommand.js
+++ b/packages/vuepress/lib/handleUnknownCommand.js
@@ -20,8 +20,8 @@ module.exports = async function (cli, options) {
   const inferredUserDocsDirectory = await inferUserDocsDirectory(pwd)
   logger.developer('inferredUserDocsDirectory', inferredUserDocsDirectory)
 
-  const needPrepareBeforeLaunchCLI = inferredUserDocsDirectory &&
-    (isHelpFlag(argv[0]) || isUnknownCommandHelp(argv))
+  const needPrepareBeforeLaunchCLI = inferredUserDocsDirectory
+    && (isHelpFlag(argv[0]) || isUnknownCommandHelp(argv))
 
   logger.developer('needPrepareBeforeLaunchCLI', needPrepareBeforeLaunchCLI)