add widget.js

public/js/widgets.js

@@ -0,0 +1,33 @@
+let iframeMap = {}
+
+const instance = 'https://nitter.net'
+const tweet_regex = /^https?:\/\/twitter\.com\/[^/]+\/status\/(\d+)\??/
+const blockquotes = document.querySelectorAll('blockquote.twitter-tweet > a')
+for (const blockquote of blockquotes) {
+  const link = blockquote.href
+  const id = tweet_regex.exec(link)[1]
+  const embed = document.createElement('iframe')
+  const url = `${instance}/i/status/${id}/embed`
+  embed.src = url
+  embed.style = 'width:100%;height:600px'
+  embed.loading = 'lazy'
+  blockquote.parentNode.replaceWith(embed)
+  if (iframeMap[url]) {
+    iframeMap[url].push(embed)
+  } else {
+    iframeMap[url] = [embed]
+  }
+}
+
+window.addEventListener('message', function(e) {
+  if (e.origin != instance || e.data[0] != 'resizeIframe')
+    return
+  
+  const data = e.data[1];
+  const height = data['h']
+  if (height == 0)
+    return
+  for (const embed of iframeMap[data['url']]) {
+    embed.style.height = `${height}px`
+  }
+}, false);