fix($core): PascalCase layouts cannot be used with camelCase nor hyph…

…en-delimited (close: #1391)

packages/@vuepress/core/lib/client/components/Content.js

@@ -1,5 +1,5 @@
 import Vue from 'vue'
-import { isPageExists, getPageAsyncComponent } from '../util'
+import { getPageAsyncComponent } from '../util'
 
 export default {
   props: {
@@ -11,8 +11,9 @@ export default {
   },
   render (h) {
     const pageKey = this.pageKey || this.$parent.$page.key
-    if (isPageExists(pageKey)) {
-      Vue.component(pageKey, getPageAsyncComponent(pageKey))
+    const pageComponent = getPageAsyncComponent(pageKey)
+    if (pageComponent) {
+      Vue.component(pageKey, pageComponent)
       return h(pageKey)
     }
     return h('')

packages/@vuepress/core/lib/client/components/GlobalLayout.vue

@@ -3,17 +3,14 @@
 </template>
 
 <script>
-import Vue from 'vue'
-
 export default {
   computed: {
     layout () {
       if (this.$page.path) {
-        if (
-          this.$vuepress.isLayoutExists(this.$page.frontmatter.layout)
-          || Boolean(Vue.component(this.$page.frontmatter.layout))
-        ) {
-          return this.$page.frontmatter.layout
+        const layout = this.$page.frontmatter.layout
+        if (layout && (this.$vuepress.getLayoutAsyncComponent(layout)
+          || this.$vuepress.getVueComponent(layout))) {
+          return layout
         }
         return 'Layout'
       }

packages/@vuepress/core/lib/client/plugins/VuePress.js

@@ -1,22 +1,18 @@
 import Store from './Store'
 import {
-  isPageExists,
-  isPageLoaded,
   getPageAsyncComponent,
-  isLayoutExists,
-  isLayoutLoaded,
-  getLayoutAsyncComponent
+  getLayoutAsyncComponent,
+  getAsyncComponent,
+  getVueComponent
 } from '../util'
 
 class VuePress extends Store {}
 
 Object.assign(VuePress.prototype, {
-  isPageExists,
-  isPageLoaded,
   getPageAsyncComponent,
-  isLayoutExists,
-  isLayoutLoaded,
-  getLayoutAsyncComponent
+  getLayoutAsyncComponent,
+  getAsyncComponent,
+  getVueComponent
 })
 
 export default {

packages/@vuepress/core/lib/client/util.js

@@ -2,36 +2,89 @@ import Vue from 'vue'
 import layoutComponents from '@internal/layout-components'
 import pageComponents from '@internal/page-components'
 
-const asyncComponents = Object.assign({}, layoutComponents, pageComponents)
-
-export function isPageExists (pageKey) {
-  return Boolean(pageComponents[pageKey])
+/**
+ * Create a cached version of a pure function.
+ */
+function cached (fn) {
+  const cache = Object.create(null)
+  // eslint-disable-next-line func-names
+  return function cachedFn (str) {
+    const hit = cache[str]
+    // eslint-disable-next-line no-return-assign
+    return hit || (cache[str] = fn(str))
+  }
 }
 
-export function isPageLoaded (pageKey) {
-  return Boolean(Vue.component(pageKey))
+/**
+ * Camelize a hyphen-delimited string.
+ */
+const camelizeRE = /-(\w)/g
+const camelize = cached(str => {
+  return str.replace(camelizeRE, (_, c) => c ? c.toUpperCase() : '')
+})
+
+/**
+ * Hyphenate a camelCase string.
+ */
+const hyphenateRE = /\B([A-Z])/g
+const hyphenate = cached(str => {
+  return str.replace(hyphenateRE, '-$1').toLowerCase()
+})
+
+/**
+ * Capitalize a string.
+ */
+const capitalize = cached(str => {
+  return str.charAt(0).toUpperCase() + str.slice(1)
+})
+
+/**
+ * This method was for securely getting Vue component when components
+ * are named in different style.
+ *
+ * e.g. a component named `a-b` can be also getted by `AB`, It's the
+ * same the other way round
+ *
+ * @param {function} getter a function of getting component by name
+ * @param {string} name component's name
+ * @returns {Component|AsyncComponent}
+ */
+export function getComponent (getter, name) {
+  if (!name) return
+  if (getter(name)) return getter(name)
+
+  const isKebabCase = name.includes('-')
+  if (isKebabCase) return getter(capitalize(camelize(name)))
+
+  return getter(capitalize(name)) || getter(hyphenate(name))
 }
 
+const asyncComponents = Object.assign({}, layoutComponents, pageComponents)
+const asyncComponentsGetter = name => asyncComponents[name]
+const pageComponentsGetter = layout => pageComponents[layout]
+const layoutComponentsGetter = layout => layoutComponents[layout]
+const globalComponentsGetter = name => Vue.component(name)
+
 export function getPageAsyncComponent (pageKey) {
-  return pageComponents[pageKey]
+  return getComponent(pageComponentsGetter, pageKey)
 }
 
-export function isLayoutExists (layout) {
-  return Boolean(layoutComponents[layout])
+export function getLayoutAsyncComponent (layout) {
+  return getComponent(layoutComponentsGetter, layout)
 }
 
-export function isLayoutLoaded (layout) {
-  return Boolean(Vue.component(layout))
+export function getAsyncComponent (name) {
+  return getComponent(asyncComponentsGetter, name)
 }
 
-export function getLayoutAsyncComponent (pageKey) {
-  return layoutComponents[pageKey]
+export function getVueComponent (name) {
+  return getComponent(globalComponentsGetter, name)
 }
 
 export function ensureAsyncComponentsLoaded (...names) {
   return Promise.all(names.filter(v => v).map(async (name) => {
-    if (!Vue.component(name) && asyncComponents[name]) {
-      const comp = await asyncComponents[name]()
+    if (!getVueComponent(name) && getAsyncComponent(name)) {
+      const comp = await getAsyncComponent(name)()
       Vue.component(name, comp.default)
     }
   }))

packages/docs/docs/theme/option-api.md

@@ -111,7 +111,8 @@ export default {
   computed: {
     layout () {
       if (this.$page.path) {
-        if (this.$vuepress.isLayoutExists(this.$frontmatter.layout)) {
+        if (this.$frontmatter.layout) {
+          // You can also check whether layout exists first as the default global layout does.
           return this.$frontmatter.layout
         }
         return 'Layout'

packages/docs/docs/zh/theme/option-api.md

@@ -111,7 +111,8 @@ export default {
   computed: {
     layout () {
       if (this.$page.path) {
-        if (this.$vuepress.isLayoutExists(this.$frontmatter.layout)) {
+        if (this.$frontmatter.layout) {
+          // 你也可以像默认的 globalLayout 一样首先检测 layout 是否存在
           return this.$frontmatter.layout
         }
         return 'Layout'