Add observers for stylesheet mutations (#177)

* hack together stylesheet observer

* Add test coverage for insertRule/deleteRule on stylesheets

* Add new observers

* update patch based on changes to master

* Functioning event recording

* Remove print statements

* Fix ID usage and mark add vs remove

* Correct type

Co-authored-by: Jon Perl <perl.jonathan@gmail.com>

src/record/index.ts

@@ -82,9 +82,11 @@ function record(options: recordOptions = {}): listenerHandler | undefined {
       inlineStylesheet,
       maskAllInputs,
     );
+
     if (!node) {
       return console.warn('Failed to snapshot the document');
     }
+
     mirror.map = idNodeMap;
     wrappedEmit(
       wrapEvent({
@@ -188,6 +190,16 @@ function record(options: recordOptions = {}): listenerHandler | undefined {
                   },
                 }),
               ),
+            styleSheetRuleCb: r =>
+              wrappedEmit(
+                wrapEvent({
+                  type: EventType.IncrementalSnapshot,
+                  data: {
+                    source: IncrementalSource.StyleSheetRule,
+                    ...r,
+                  },
+                }),
+              ),
             blockClass,
             ignoreClass,
             maskAllInputs,

src/record/observer.ts

@@ -21,6 +21,7 @@ import {
   MouseInteractions,
   listenerHandler,
   scrollCallback,
+  styleSheetRuleCallback,
   viewportResizeCallback,
   inputValue,
   inputCallback,
@@ -519,6 +520,31 @@ function initInputObserver(
   };
 }
 
+function initStyleSheetObserver(cb: styleSheetRuleCallback): listenerHandler {
+  const insertRule = CSSStyleSheet.prototype.insertRule;
+  CSSStyleSheet.prototype.insertRule = function(rule: string, index?: number) {
+    cb({
+      id: mirror.getId(this.ownerNode as INode),
+      adds: [{ rule, index }],
+    });
+    return insertRule.apply(this, arguments);
+  };
+
+  const deleteRule = CSSStyleSheet.prototype.deleteRule;
+  CSSStyleSheet.prototype.deleteRule = function(index: number) {
+    cb({
+      id: mirror.getId(this.ownerNode as INode),
+      removes: [{ index }],
+    });
+    return deleteRule.apply(this, arguments);
+  };
+
+  return () => {
+    CSSStyleSheet.prototype.insertRule = insertRule;
+    CSSStyleSheet.prototype.deleteRule = deleteRule;
+  };
+}
+
 function initMediaInteractionObserver(
   mediaInteractionCb: mediaInteractionCallback,
   blockClass: blockClass,
@@ -548,6 +574,7 @@ function mergeHooks(o: observerParam, hooks: hooksParam) {
     viewportResizeCb,
     inputCb,
     mediaInteractionCb,
+    styleSheetRuleCb,
   } = o;
   o.mutationCb = (...p: Arguments<mutationCallBack>) => {
     if (hooks.mutation) {
@@ -591,6 +618,12 @@ function mergeHooks(o: observerParam, hooks: hooksParam) {
     }
     mediaInteractionCb(...p);
   };
+  o.styleSheetRuleCb = (...p: Arguments<styleSheetRuleCallback>) => {
+    if (hooks.styleSheetRule) {
+      hooks.styleSheetRule(...p);
+    }
+    styleSheetRuleCb(...p);
+  };
 }
 
 export default function initObservers(
@@ -621,6 +654,8 @@ export default function initObservers(
     o.mediaInteractionCb,
     o.blockClass,
   );
+  const styleSheetObserver = initStyleSheetObserver(o.styleSheetRuleCb);
+
   return () => {
     mutationObserver.disconnect();
     mousemoveHandler();
@@ -629,5 +664,6 @@ export default function initObservers(
     viewportResizeHandler();
     inputHandler();
     mediaInteractionHandler();
+    styleSheetObserver();
   };
 }

src/types.ts

@@ -52,6 +52,8 @@ export type customEvent<T = unknown> = {
   };
 };
 
+export type styleSheetEvent = {};
+
 export enum IncrementalSource {
   Mutation,
   MouseMove,
@@ -61,6 +63,7 @@ export enum IncrementalSource {
   Input,
   TouchMove,
   MediaInteraction,
+  StyleSheetRule,
 }
 
 export type mutationData = {
@@ -93,6 +96,10 @@ export type mediaInteractionData = {
   source: IncrementalSource.MediaInteraction;
 } & mediaInteractionParam;
 
+export type styleSheetRuleData = {
+  source: IncrementalSource.StyleSheetRule;
+} & styleSheetRuleParam;
+
 export type incrementalData =
   | mutationData
   | mousemoveData
@@ -100,7 +107,8 @@ export type incrementalData =
   | scrollData
   | viewportResizeData
   | inputData
-  | mediaInteractionData;
+  | mediaInteractionData
+  | styleSheetRuleData;
 
 export type event =
   | domContentLoadedEvent
@@ -141,6 +149,7 @@ export type observerParam = {
   ignoreClass: string;
   maskAllInputs: boolean;
   inlineStylesheet: boolean;
+  styleSheetRuleCb: styleSheetRuleCallback;
   mousemoveWait: number;
 };
 
@@ -152,6 +161,7 @@ export type hooksParam = {
   viewportResize?: viewportResizeCallback;
   input?: inputCallback;
   mediaInteaction?: mediaInteractionCallback;
+  styleSheetRule?: styleSheetRuleCallback;
 };
 
 export type textCursor = {
@@ -239,6 +249,23 @@ export type scrollPosition = {
 
 export type scrollCallback = (p: scrollPosition) => void;
 
+export type styleSheetAddRule = {
+  rule: string;
+  index?: number;
+};
+
+export type styleSheetDeleteRule = {
+  index: number;
+};
+
+export type styleSheetRuleParam = {
+  id: number;
+  removes?: styleSheetDeleteRule[];
+  adds?: styleSheetAddRule[];
+};
+
+export type styleSheetRuleCallback = (s: styleSheetRuleParam) => void;
+
 export type viewportResizeDimention = {
   width: number;
   height: number;