diff --git a/src/replay/index.ts b/src/replay/index.ts
index 23dad8bc..61ed5b8e 100644
--- a/src/replay/index.ts
+++ b/src/replay/index.ts
@@ -754,10 +754,10 @@ export class Replayer {
         !this.imageMap.has(event)
       ) {
         count++;
-        var canvas = document.createElement('canvas');
-        var ctx = canvas.getContext('2d');
-        var imgd = ctx?.createImageData(canvas.width, canvas.height);
-        var d = imgd?.data;
+        const canvas = document.createElement('canvas');
+        const ctx = canvas.getContext('2d');
+        const imgd = ctx?.createImageData(canvas.width, canvas.height);
+        let d = imgd?.data;
         d = JSON.parse(event.data.args[0]);
         ctx?.putImageData(imgd!, 0, 0);
       }
diff --git a/typings/record/observer.d.ts b/typings/record/observer.d.ts
index a82a370c..b77aa4ee 100644
--- a/typings/record/observer.d.ts
+++ b/typings/record/observer.d.ts
@@ -1,9 +1,10 @@
 import { MaskInputOptions, SlimDOMOptions } from 'rrweb-snapshot';
-import { mutationCallBack, observerParam, listenerHandler, blockClass, maskTextClass, hooksParam, MaskTextFn, Mirror } from '../types';
+import { mutationCallBack, observerParam, listenerHandler, scrollCallback, blockClass, maskTextClass, hooksParam, SamplingStrategy, MaskTextFn, Mirror } from '../types';
 import MutationBuffer from './mutation';
 import { IframeManager } from './iframe-manager';
 import { ShadowDomManager } from './shadow-dom-manager';
 export declare const mutationBuffers: MutationBuffer[];
 export declare function initMutationObserver(cb: mutationCallBack, doc: Document, blockClass: blockClass, blockSelector: string | null, maskTextClass: maskTextClass, maskTextSelector: string | null, inlineStylesheet: boolean, maskInputOptions: MaskInputOptions, maskTextFn: MaskTextFn | undefined, recordCanvas: boolean, slimDOMOptions: SlimDOMOptions, mirror: Mirror, iframeManager: IframeManager, shadowDomManager: ShadowDomManager, rootEl: Node): MutationObserver;
+export declare function initScrollObserver(cb: scrollCallback, doc: Document, mirror: Mirror, blockClass: blockClass, sampling: SamplingStrategy): listenerHandler;
 export declare const INPUT_TAGS: string[];
 export declare function initObservers(o: observerParam, hooks?: hooksParam): listenerHandler;
diff --git a/typings/record/shadow-dom-manager.d.ts b/typings/record/shadow-dom-manager.d.ts
index b0c4e2bc..0d7fca02 100644
--- a/typings/record/shadow-dom-manager.d.ts
+++ b/typings/record/shadow-dom-manager.d.ts
@@ -1,4 +1,4 @@
-import { mutationCallBack, blockClass, maskTextClass, MaskTextFn, Mirror } from '../types';
+import { mutationCallBack, blockClass, maskTextClass, MaskTextFn, Mirror, scrollCallback, SamplingStrategy } from '../types';
 import { MaskInputOptions, SlimDOMOptions } from 'rrweb-snapshot';
 import { IframeManager } from './iframe-manager';
 declare type BypassOptions = {
@@ -10,15 +10,18 @@ declare type BypassOptions = {
     maskInputOptions: MaskInputOptions;
     maskTextFn: MaskTextFn | undefined;
     recordCanvas: boolean;
+    sampling: SamplingStrategy;
     slimDOMOptions: SlimDOMOptions;
     iframeManager: IframeManager;
 };
 export declare class ShadowDomManager {
     private mutationCb;
+    private scrollCb;
     private bypassOptions;
     private mirror;
     constructor(options: {
         mutationCb: mutationCallBack;
+        scrollCb: scrollCallback;
         bypassOptions: BypassOptions;
         mirror: Mirror;
     });
diff --git a/typings/replay/index.d.ts b/typings/replay/index.d.ts
index 9c849ae2..0a2af1c8 100644
--- a/typings/replay/index.d.ts
+++ b/typings/replay/index.d.ts
@@ -24,6 +24,7 @@ export declare class Replayer {
     private newDocumentQueue;
     constructor(events: Array<eventWithTime | string>, config?: Partial<playerConfig>);
     on(event: string, handler: Handler): this;
+    off(event: string, handler: Handler): this;
     setConfig(config: Partial<playerConfig>): void;
     getMetaData(): playerMetaData;
     getCurrentTime(): number;