fix: cross-origin url cannot be redirected when "externalLinkTarget" is set to "_self" and "routerMode" is set to "history". (#1062)

* [fix #1046] fix cross-origin url cannot be redirected when  "externalLinkTarget" is set to "_self" and "routerMode" is set to "history".

* [code format] code format.

* update docs

* docs refine.

* fix(core): cross-orgin link work incorrect (#1046)

Fix cross-origin url cannot be redirected when "externalLinkTarget" is set to "_self" and "routerMode" is set to "history". 
Add new configuration for those cases and completed docs.

Fixes #1046

PR Close #1062

Author: Koooooo-7

Diff for: docs/helpers.md

@@ -65,6 +65,14 @@ You will get `<a href="/demo/">link</a>`html. Do not worry, you can still set ti
 [link](/demo ':disabled')
 ```
 
+## Cross-Origin link
+
+Only when you both set the `routerMode: 'history'` and `externalLinkTarget: '_self'`, you need add this configuration for those Cross-Origin links.
+
+```md
+[example.com](https://example.com/ ':crossorgin')  
+```
+
 ## Github Task Lists
 
 ```md

Diff for: src/core/config.js

@@ -32,6 +32,7 @@ export default function() {
       externalLinkRel: 'noopener',
       routerMode: 'hash',
       noCompileLinks: [],
+      crossOriginLinks: [],
       relativePath: false,
       topMargin: 0,
     },

Diff for: src/core/render/compiler/link.js

@@ -30,6 +30,17 @@ export const linkCompiler = ({ renderer, router, linkTarget, compilerClass }) =>
       attrs.push(`target="${config.target}"`);
     }
 
+    // special case to check crossorigin urls
+    if (
+      config.crossorgin &&
+      linkTarget === '_self' &&
+      compilerClass.config.routerMode === 'history'
+    ) {
+      if (compilerClass.config.crossOriginLinks.indexOf(href) === -1) {
+        compilerClass.config.crossOriginLinks.push(href);
+      }
+    }
+
     if (config.disabled) {
       attrs.push('disabled');
       href = 'javascript:void(0)';

Diff for: src/core/router/history/html5.js

@@ -27,7 +27,12 @@ export class HTML5History extends History {
       if (el.tagName === 'A' && !/_blank/.test(el.target)) {
         e.preventDefault();
         const url = el.href;
-        window.history.pushState({ key: url }, '', url);
+        // solve history.pushState cross-origin issue
+        if (this.config.crossOriginLinks.indexOf(url) !== -1) {
+          window.open(url, '_self');
+        } else {
+          window.history.pushState({ key: url }, '', url);
+        }
         cb({ event: e, source: 'navigate' });
       }
     });