feat(Axe): using defaultConfig to axe and add docs

Author: ktquez

Diff for: config/defaultThemeConfig.js

@@ -5,3 +5,7 @@ export const colorMode = {
     modes: ['light', 'dark', 'system', 'sepia']
   }
 }
+
+export const axe = {
+  enabled: true
+}

Diff for: docs/guide/config.md

@@ -63,10 +63,6 @@ module.exports = {
   }
 ```
 
-## Skip to
-
-Pretty soon
-
 ## Announcer
 
 The [@vue-a11y/announcer](https://github.com/vue-a11y/vue-announcer) provides an easy way for people using screen readers to know what’s going on in your app.
@@ -104,3 +100,31 @@ module.exports = {
     }
   }
 ```
+
+## Axe
+
+We use the `axe` property in `$themeConfig` to customize the vue-axe package.
+
+```javascript
+// e.g. docs/.vuepress/config.js
+module.exports = {
+  theme: 'vuepress-theme-default-vue-a11y',
+  // ...
+  themeConfig: {
+    axe: {
+      enabled: true,
+      options: {
+        clearConsoleOnUpdate: true
+      }
+    }
+  }
+```
+
+::: tip
+See more config options available in VueAxe:  
+[https://github.com/vue-a11y/vue-axe#configuration](https://github.com/vue-a11y/vue-axe#configuration)
+:::
+
+## Skip to
+
+Pretty soon

Diff for: enhanceApp.js

@@ -1,12 +1,18 @@
 import VueAnnouncer from '@vue-a11y/announcer'
 import VueDarkMode from '@vue-a11y/dark-mode'
 import 'a11y-css-reset/combo.css'
+import merge from 'deepmerge'
 import VueSkipTo from 'vue-skip-to'
+import { axe as axeDefaultConfig } from './config/defaultThemeConfig'
+import { isObject } from './utils'
 
-export default ({ Vue, router, isServer }) => {
+export default ({ Vue, router, isServer, siteData }) => {
   if (process.env.NODE_ENV === 'development') {
-    const VueAxe = require('vue-axe').default
-    Vue.use(VueAxe)
+    const axeConfig = siteData.themeConfig.axe && isObject(siteData.themeConfig.axe) ? merge(axeDefaultConfig, siteData.themeConfig.axe) : axeDefaultConfig
+    if (axeConfig.enabled) {
+      const VueAxe = require('vue-axe').default
+      Vue.use(VueAxe, axeConfig.options)
+    }
   }
   if (!isServer) {
     Vue.use(VueSkipTo)

Diff for: utils/index.js

@@ -0,0 +1,3 @@
+export function isObject (item) {
+  return (item && typeof item === 'object' && !Array.isArray(item))
+}