perf: optimize performance of the DoubleLinkedList get (rrweb-io#1220)

* perf: optimize performance of the DoubleLinkedList get * fix: delete addedNodeIndexArr
eoghanmurray · Jul 27, 2023 · 48b5f7b · 48b5f7b
1 parent 5aba92f
commit 48b5f7b
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Showing 4 changed files with 60 additions and 2 deletions.
diff --git a/.changeset/gold-terms-look.md b/.changeset/gold-terms-look.md
@@ -0,0 +1,5 @@
+---
+'rrweb': patch
+---
+
+perf: optimize performance of the DoubleLinkedList get
diff --git a/packages/rrweb/src/record/mutation.ts b/packages/rrweb/src/record/mutation.ts
@@ -48,6 +48,7 @@ function isNodeInLinkedList(n: Node | NodeInLinkedList): n is NodeInLinkedList {
 class DoubleLinkedList {
   public length = 0;
   public head: DoubleLinkedListNode | null = null;
+  public tail: DoubleLinkedListNode | null = null;
 
   public get(position: number) {
     if (position >= this.length) {
@@ -95,6 +96,9 @@ class DoubleLinkedList {
       node.next = this.head;
       this.head = node;
     }
+    if (node.next === null) {
+      this.tail = node;
+    }
     this.length++;
   }
 
@@ -108,11 +112,15 @@ class DoubleLinkedList {
       this.head = current.next;
       if (this.head) {
         this.head.previous = null;
+      } else {
+        this.tail = null;
       }
     } else {
       current.previous.next = current.next;
       if (current.next) {
         current.next.previous = current.previous;
+      } else {
+        this.tail = current.previous;
       }
     }
     if (n.__ln) {
@@ -368,8 +376,10 @@ export default class MutationBuffer {
         }
       }
       if (!node) {
-        for (let index = addList.length - 1; index >= 0; index--) {
-          const _node = addList.get(index);
+        let tailNode = addList.tail;
+        while (tailNode) {
+          const _node = tailNode;
+          tailNode = tailNode.previous;
           // ensure _node is defined before attempting to find value
           if (_node) {
             const parentId = this.mirror.getId(_node.value.parentNode);

diff --git a/packages/rrweb/test/benchmark/dom-mutation.test.ts b/packages/rrweb/test/benchmark/dom-mutation.test.ts
@@ -36,6 +36,12 @@ const suites: Array<
     eval: 'window.workload()',
     times: 5,
   },
+  {
+    title: 'create 10000 DOM nodes and move it to new container',
+    html: 'benchmark-dom-mutation-add-and-move.html',
+    eval: 'window.workload()',
+    times: 5,
+  },
 ];
 
 function avg(v: number[]): number {

diff --git a/packages/rrweb/test/html/benchmark-dom-mutation-add-and-move.html b/packages/rrweb/test/html/benchmark-dom-mutation-add-and-move.html
@@ -0,0 +1,37 @@
+<html>
+  <body>
+    <div id="app"></div>
+  </body>
+  <script>
+    function appendNodes(parentNode, total) {
+      const el = document.createElement('div');
+      for (let i = 0; i < total; i++) {
+        const div = document.createElement('div');
+        div.innerHTML = `div-${i + 1}`;
+        el.append(div);
+      }
+      parentNode.append(el);
+      return el;
+    }
+
+    function addAndMove() {
+      const app = document.getElementById('app');
+
+      const elContainer = appendNodes(app, 10000);
+
+      const newAppContainer = document.createElement('div');
+
+      newAppContainer.append(elContainer);
+
+      document.body.append(newAppContainer);
+
+      app.remove();
+
+      // necessary
+      appendNodes(document.body, 1);
+    }
+    window.workload = () => {
+      addAndMove();
+    };
+  </script>
+</html>