Eslint camelCase (rrweb-io#1625)

* Add eslint rule to flag up me forgetting to camelCase - I'd say I introduced all the snake_cases that are fixed here
* Allow some dubious snake cases for now; we could examine again whether they can be converted to `camelCase['snake_var']` if we need to maintain backwards compatibility of output
* add ESLINT_USE_FLAT_CONFIG against eslint v8.57.0 in order to continue using the deprecated .eslintrc.js method

Author: eoghanmurray

.changeset/eslint-camelcase-devonly.md

@@ -0,0 +1,2 @@
+---
+---

.eslintrc.js

@@ -23,5 +23,8 @@ module.exports = {
   rules: {
     'tsdoc/syntax': 'warn',
     '@typescript-eslint/prefer-as-const': 'warn',
+    'camelcase': ['error', {
+      allow: ['rr_.*', 'legacy_.*', 'UNSAFE_.*', '__rrweb_.*'],
+    }],
   },
 };

package.json

@@ -53,8 +53,8 @@
     "dev": "yarn turbo run dev --concurrency=18",
     "repl": "cd packages/rrweb && npm run repl",
     "live-stream": "cd packages/rrweb && yarn live-stream",
-    "lint": "yarn run concurrently --success=all -r -m=1 'yarn run markdownlint docs' 'yarn eslint packages/*/src --ext .ts,.tsx,.js,.jsx,.svelte'",
-    "lint:report": "yarn eslint --output-file eslint_report.json --format json packages/*/src --ext .ts,.tsx,.js,.jsx",
+    "lint": "yarn run concurrently --success=all -r -m=1 'yarn run markdownlint docs' 'ESLINT_USE_FLAT_CONFIG=false yarn eslint packages/*/src --ext .ts,.tsx,.js,.jsx,.svelte'",
+    "lint:report": "ESLINT_USE_FLAT_CONFIG=false yarn eslint --output-file eslint_report.json --format json packages/*/src --ext .ts,.tsx,.js,.jsx",
     "release": "yarn build:all && changeset publish"
   },
   "resolutions": {

packages/rrweb/src/replay/index.ts

@@ -760,30 +760,30 @@ export class Replayer {
       this.service.send({ type: 'CAST_EVENT', payload: { event } });
 
       // events are kept sorted by timestamp, check if this is the last event
-      const last_index = this.service.state.context.events.length - 1;
+      const lastIndex = this.service.state.context.events.length - 1;
       if (
         !this.config.liveMode &&
-        event === this.service.state.context.events[last_index]
+        event === this.service.state.context.events[lastIndex]
       ) {
         const finish = () => {
-          if (last_index < this.service.state.context.events.length - 1) {
+          if (lastIndex < this.service.state.context.events.length - 1) {
             // more events have been added since the setTimeout
             return;
           }
           this.backToNormal();
           this.service.send('END');
           this.emitter.emit(ReplayerEvents.Finish);
         };
-        let finish_buffer = 50; // allow for checking whether new events aren't just about to be loaded in
+        let finishBuffer = 50; // allow for checking whether new events aren't just about to be loaded in
         if (
           event.type === EventType.IncrementalSnapshot &&
           event.data.source === IncrementalSource.MouseMove &&
           event.data.positions.length
         ) {
           // extend finish event if the last event is a mouse move so that the timer isn't stopped by the service before checking the last event
-          finish_buffer += Math.max(0, -event.data.positions[0].timeOffset);
+          finishBuffer += Math.max(0, -event.data.positions[0].timeOffset);
         }
-        setTimeout(finish, finish_buffer);
+        setTimeout(finish, finishBuffer);
       }
 
       this.emitter.emit(ReplayerEvents.EventCast, event);