Migrate to Docusaurus V2 🐱‍🐉 (#412)

* Migrate to Docusaurus V2

* Add redirects

Only covers most recent version

* Add omitted scripts folder

* Include working yarn.lock

static/js/discourse_discussion.jsx

@@ -0,0 +1,112 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+export default class DiscussionBox extends React.Component {
+
+  constructor(props) {
+    super(props);
+    this.postMessageReceived = this.postMessageReceived.bind(this);
+  }
+
+  componentDidMount() {
+    this.DiscourseEmbed = {
+      discourseUrl: this.props.discourseUrl,
+      discourseEmbedUrl: this.props.discourseEmbedUrl,
+    };
+    window.addEventListener('message', this.postMessageReceived, false);
+  }
+
+  componentWillUnmount() {
+    window.removeEventListener('message', this.postMessageReceived);
+  }
+
+  getIframeSource() {
+    const { discourseUrl, discourseEmbedUrl, discourseUserName } = this.props;
+    const queryParams = {};
+
+    if (discourseEmbedUrl) {
+      if (discourseEmbedUrl.indexOf('/') === 0) {
+        console.error('discourseEmbedUrl must be a full URL, not a relative path');
+      }
+
+      queryParams.embed_url = encodeURIComponent(discourseEmbedUrl);
+    }
+
+    if (discourseUserName) {
+      queryParams.discourse_username = discourseUserName;
+    }
+
+    let src = discourseUrl + 'embed/comments';
+    const keys = Object.keys(queryParams);
+    if (keys.length > 0) {
+      src += '?';
+
+      for (let i = 0; i < keys.length; i++) {
+        if (i > 0) { src += '&'; }
+
+        const k = keys[i];
+        src += k + '=' + queryParams[k];
+      }
+    }
+
+    return src;
+  }
+
+  postMessageReceived(e) {
+    if (!e) { return; }
+
+    const iframe = this.iframe;
+    const { discourseUrl } = this.props;
+
+    if (normalizeUrl(discourseUrl).indexOf(normalizeUrl(e.origin)) === -1) { return; }
+
+    if (e.data) {
+      if (e.data.type === 'discourse-resize' && e.data.height) {
+        iframe.height = e.data.height + 'px';
+      }
+
+      if (e.data.type === 'discourse-scroll' && e.data.top) {
+        // find iframe offset
+        const destY = findPosY(iframe) + e.data.top;
+        window.scrollTo(0, destY);
+      }
+    }
+  }
+
+  render() {
+    return (
+      <div
+        className='discussion-box-container'
+      >
+        <iframe
+          title='discussion box'
+          ref={(el) => { this.iframe = el; }}
+          src={this.getIframeSource()}
+          id='discourse-embed-frame'
+          width='100%'
+          frameBorder='0'
+        />
+      </div>
+    );
+  }
+}
+
+function normalizeUrl(url) {
+  return url.toLowerCase().replace(/^https?(\:\/\/)?/, '');
+}
+
+function findPosY(obj) {
+  let top = 0;
+  if (obj.offsetParent) {
+    while (1) {
+      top += obj.offsetTop;
+      if (!obj.offsetParent) {
+        break;
+      }
+      obj = obj.offsetParent;
+    }
+  } else if (obj.y) {
+    top += obj.y;
+  }
+  return top;
+}