Save edited code in localStorage

Author: JoshStern

html/js/ejs.js

@@ -83,7 +83,8 @@ window.addEventListener("load", () => {
       localStorage.setItem("usedSandbox", "true")
     }
 
-    let code = node.textContent
+    const codeId = node.firstChild.id
+    let code = localStorage.getItem(codeId) || node.textContent
     let wrap = node.parentNode.insertBefore(elt("div", {"class": "editor-wrap"}), node)
     let editor = CodeMirror(div => wrap.insertBefore(div, wrap.firstChild), {
       value: code,
@@ -103,6 +104,7 @@ window.addEventListener("load", () => {
       clearTimeout(pollingScroll)
       pollingScroll = setTimeout(pollScroll, 500)
     })
+    editor.on("change", debounce(() => localStorage.setItem(codeId, editor.getValue()), 250))
     wrap.style.marginLeft = wrap.style.marginRight = -Math.min(article.offsetLeft, 100) + "px"
     setTimeout(() => editor.refresh(), 600)
     if (e) {
@@ -228,4 +230,12 @@ window.addEventListener("load", () => {
       window.scrollBy(0, newBot - bot)
     }
   }
+
+  function debounce(fn, delay = 50) {
+    let timeout
+    return () => {
+      if (timeout) clearTimeout(timeout)
+      timeout = setTimeout(() => fn.apply(null, arguments), delay)
+    }
+  }
 })