Improve Parser docs

src/parser/config/config.js

@@ -5,11 +5,17 @@ export default {
   // @see https://grapesjs.com/docs/guides/Custom-CSS-parser.html
   parserCss: null,
 
+  // Custom HTML parser
+  // At the moment, the custom HTML parser should rely on DOM Node instance as the result
+  // @example
+  // The return should be an instance of an Node as the root to traverse
+  // https://developer.mozilla.org/en-US/docs/Web/API/Node
+  // parserHtml: (input, opts = {}) => (new DOMParser()).parseFromString(input, 'text/xml')
+  // Here the result will be XMLDocument, which extends Node
+  parserHtml: null,
+
   // DOMParser mime type (default 'text/html')
   // @see https://developer.mozilla.org/en-US/docs/Web/API/DOMParser/parseFromString
   // If you use the `text/html` parser, it will fix the invalid syntax automatically
-  htmlType: null,
-
-  // TODO: Custom HTML parser
-  parserHtml: null
+  htmlType: null
 };

src/parser/model/ParserHtml.js

@@ -1,4 +1,4 @@
-import { each, isString } from 'underscore';
+import { each, isString, isFunction } from 'underscore';
 import BrowserParserHtml from './BrowserParserHtml';
 
 export default config => {
@@ -287,7 +287,9 @@ export default config => {
       const conf = (em && em.get('Config')) || {};
       const res = { html: null, css: null };
       const cf = { ...config, ...opts };
-      const el = BrowserParserHtml(str, cf);
+      const el = isFunction(cf.parserHtml)
+        ? cf.parserHtml(str, cf)
+        : BrowserParserHtml(str, cf);
       const scripts = el.querySelectorAll('script');
       let i = scripts.length;