feat: new @bbob/html api (#4)

packages/bbob-react/src/render.js

@@ -1,33 +1,25 @@
 import React from 'react';
 import core from '@bbob/core';
-import html from '@bbob/html';
+import * as html from '@bbob/html';
 
 import { isTagNode, isStringNode } from '@bbob/plugin-helper';
 
 const toAST = (source, plugins) => core(plugins)
   .process(source, {
-    render: input => html(input, { stripTags: true }),
+    render: input => html.render(input, { stripTags: true }),
   }).tree;
 
 function tagToReactElement(node) {
-  if (node.content === null) {
-    return React.createElement(
-      node.tag,
-      node.attrs,
-      null,
-    );
-  }
-
   return React.createElement(
     node.tag,
     node.attrs,
     // eslint-disable-next-line no-use-before-define
-    renderToReactNodes(node.content),
+    node.content ? renderToReactNodes(node.content) : null,
   );
 }
 
 function renderToReactNodes(nodes) {
-  const els = nodes.reduce((arr, node) => {
+  const els = [].concat(nodes).reduce((arr, node) => {
     if (isTagNode(node)) {
       arr.push(tagToReactElement(node));
     } else if (isStringNode(node)) {