diff --git a/.eslintrc.json b/.eslintrc.json
index a98dc4c77a..83668f2826 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -25,6 +25,7 @@
   },
 
   "rules": {
+    "comma-dangle": ["error", "only-multiline"],
     "eol-last": "error",
     "no-empty": "off",
     "no-console": "off",
diff --git a/bin/build-utils.js b/bin/build-utils.js
index 29aa599562..41ccbc0071 100644
--- a/bin/build-utils.js
+++ b/bin/build-utils.js
@@ -48,9 +48,7 @@ function doBrowserify(pkgName, filepath, opts, exclude) {
             path.dirname(filepath) + '/' + path.basename(filepath));
         });
     } else {
-      bundler = browserify(addPath(pkgName, filepath), opts)
-        .transform('es3ify')
-        .plugin('bundle-collapser/plugin');
+      bundler = browserify(addPath(pkgName, filepath), opts);
     }
 
     if (exclude) {
diff --git a/bin/test-browser.js b/bin/test-browser.js
index f0f91e2826..5d32585abc 100755
--- a/bin/test-browser.js
+++ b/bin/test-browser.js
@@ -6,12 +6,16 @@ const playwright = require('playwright');
 const { identity, pickBy } = require('lodash');
 
 var MochaSpecReporter = require('mocha').reporters.Spec;
+const createMochaStatsCollector = require('mocha/lib/stats-collector');
 
 var devserver = require('./dev-server.js');
 
 // BAIL=0 to disable bailing
 var bail = process.env.BAIL !== '0';
 
+// Track if the browser has closed at the request of this script, or due to an external event.
+let closeRequested;
+
 // Playwright BrowserType whitelist.
 // See: https://playwright.dev/docs/api/class-playwright
 const SUPPORTED_BROWSERS = [ 'chromium', 'firefox', 'webkit' ];
@@ -56,33 +60,51 @@ const qs = {
 testUrl += '?';
 testUrl += new URLSearchParams(pickBy(qs, identity));
 
+class ArrayMap extends Map {
+  get(key) {
+    if (!this.has(key)) {
+      this.set(key, []);
+    }
+    return super.get(key);
+  }
+}
+
 class RemoteRunner {
   constructor(browser) {
     this.browser = browser;
-    this.handlers = {};
+    this.handlers = new ArrayMap();
+    this.onceHandlers = new ArrayMap();
     this.handleEvent = this.handleEvent.bind(this);
+    createMochaStatsCollector(this);
+  }
+
+  once(name, handler) {
+    this.onceHandlers.get(name).push(handler);
   }
 
   on(name, handler) {
-    var handlers = this.handlers;
+    this.handlers.get(name).push(handler);
+  }
 
-    if (!handlers[name]) {
-      handlers[name] = [];
-    }
-    handlers[name].push(handler);
+  triggerHandlers(eventName, handlerArgs) {
+    const triggerHandler = handler => handler.apply(null, handlerArgs);
+
+    this.onceHandlers.get(eventName).forEach(triggerHandler);
+    this.onceHandlers.delete(eventName);
+
+    this.handlers.get(eventName).forEach(triggerHandler);
   }
 
   async handleEvent(event) {
     try {
       var additionalProps = ['pass', 'fail', 'pending'].indexOf(event.name) === -1 ? {} : {
         slow: event.obj.slow ? function () { return event.obj.slow; } : function () { return 60; },
-        fullTitle: event.obj.fullTitle ? function () { return event.obj.fullTitle; } : undefined
+        fullTitle: event.obj.fullTitle ? function () { return event.obj.fullTitle; } : undefined,
+        titlePath: event.obj.titlePath ? function () { return event.obj.titlePath; } : undefined,
       };
       var obj = Object.assign({}, event.obj, additionalProps);
 
-      this.handlers[event.name].forEach(function (handler) {
-        handler(obj, event.err);
-      });
+      this.triggerHandlers(event.name, [ obj, event.err ]);
 
       switch (event.name) {
         case 'fail': this.handleFailed(); break;
@@ -91,12 +113,14 @@ class RemoteRunner {
     } catch (e) {
       console.error('Tests failed:', e);
 
+      closeRequested = true;
       await this.browser.close();
       process.exit(3);
     }
   }
 
   async handleEnd(failed) {
+    closeRequested = true;
     await this.browser.close();
     process.exit(!process.env.PERF && failed ? 1 : 0);
   }
@@ -104,9 +128,7 @@ class RemoteRunner {
   handleFailed() {
     if (bail) {
       try {
-        this.handlers['end'].forEach(function (handler) {
-          handler();
-        });
+        this.triggerHandlers('end');
       } catch (e) {
         console.log('An error occurred while bailing:', e);
       } finally {
@@ -147,8 +169,20 @@ async function startTest() {
     headless: true,
   };
   const browser = await playwright[browserName].launch(options);
+
   const page = await browser.newPage();
 
+  // Playwright's Browser.on('close') event handler would be the more obvious
+  // choice here, but it does not seem to be triggered if the browser is closed
+  // by an external event (e.g. process is killed, user closes non-headless
+  // browser window).
+  page.on('close', () => {
+    if (!closeRequested) {
+      console.log('!!! Browser closed by external event.');
+      process.exit(1);
+    }
+  });
+
   const runner = new RemoteRunner(browser);
   new MochaSpecReporter(runner);
   new BenchmarkConsoleReporter(runner);
diff --git a/bin/test-node.sh b/bin/test-node.sh
index c2a7f03159..1ab2b0a9af 100755
--- a/bin/test-node.sh
+++ b/bin/test-node.sh
@@ -37,7 +37,9 @@ fi
 if [ "$PERF" ]; then
     node tests/performance/index.js
 elif [ ! "$COVERAGE" ]; then
+    # --exit required to workaround #8839
     ./node_modules/.bin/mocha \
+        --exit \
         "$BAIL_OPT" \
         --timeout "$TIMEOUT" \
         --require=./tests/integration/node.setup.js \
@@ -45,9 +47,11 @@ elif [ ! "$COVERAGE" ]; then
         --grep="$GREP" \
         "$TESTS_PATH"
 else
+    # --exit required to workaround #8839
     ./node_modules/.bin/istanbul cover \
        --no-default-excludes -x 'tests/**' -x 'node_modules/**' \
        ./node_modules/mocha/bin/_mocha -- \
+        --exit \
         "$BAIL_OPT" \
         --timeout "$TIMEOUT" \
         --require=./tests/integration/node.setup.js \
diff --git a/package.json b/package.json
index a283289395..c09ce4f90f 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,7 @@
     "build-modules": "node bin/build-modules.js",
     "test-unit": "mocha tests/unit",
     "test-node": "./bin/test-node.sh",
-    "test-component": "mocha tests/component",
+    "test-component": "mocha --exit tests/component # --exit for #8839",
     "test-fuzzy": "TYPE=fuzzy npm run test",
     "test-browser": "npm run build-test && node ./bin/test-browser.js",
     "test-memleak": "mocha -gc tests/memleak",
@@ -41,7 +41,7 @@
     "abort-controller": "3.0.0",
     "clone-buffer": "1.0.0",
     "double-ended-queue": "2.1.0-0",
-    "fetch-cookie": "0.11.0",
+    "fetch-cookie": "2.1.0",
     "fruitdown": "1.0.2",
     "immediate": "3.3.0",
     "level": "6.0.1",
@@ -66,7 +66,6 @@
     "browserify": "16.4.0",
     "browserify-incremental": "3.1.1",
     "builtin-modules": "3.1.0",
-    "bundle-collapser": "1.3.0",
     "chai": "3.5.0",
     "chai-as-promised": "5.3.0",
     "change-case": "4.0.1",
@@ -74,7 +73,6 @@
     "cssmin": "0.4.3",
     "denodeify": "1.2.1",
     "derequire": "2.1.1",
-    "es3ify": "0.2.2",
     "eslint": "8.7.0",
     "express": "4.17.0",
     "express-pouchdb": "4.2.0",
@@ -90,7 +88,7 @@
     "marky": "1.2.0",
     "median": "0.0.2",
     "mkdirp": "0.5.1",
-    "mocha": "3.5.0",
+    "mocha": "10.2.0",
     "mockery": "2.1.0",
     "ncp": "2.0.0",
     "playwright": "1.36.1",
diff --git a/tests/component/test.deletion_error.js b/tests/component/test.deletion_error.js
index 62902b1c7c..2f07520da1 100644
--- a/tests/component/test.deletion_error.js
+++ b/tests/component/test.deletion_error.js
@@ -29,8 +29,8 @@ describe('test.deletion_error.js', function () {
     server = app.listen(0);
   });
 
-  after(function () {
-    return server.close();
+  after(function (done) {
+    server.close(done);
   });
 
   it('Test error during deletion', function () {
diff --git a/tests/component/test.read_only_replication.js b/tests/component/test.read_only_replication.js
index d070878edd..55040cf059 100644
--- a/tests/component/test.read_only_replication.js
+++ b/tests/component/test.read_only_replication.js
@@ -38,8 +38,8 @@ describe('test.read_only_replication.js', function () {
     server = app.listen(0);
   });
 
-  after(function () {
-    return server.close();
+  after(function (done) {
+    server.close(done);
   });
 
   it('Test checkpointer handles error codes', function () {
diff --git a/tests/component/test.replication_perf_regression.js b/tests/component/test.replication_perf_regression.js
index 953d1119ef..84595cdd3b 100644
--- a/tests/component/test.replication_perf_regression.js
+++ b/tests/component/test.replication_perf_regression.js
@@ -34,8 +34,8 @@ describe('test.replication_perf_regression.js', function () {
     };
   });
 
-  after(function () {
-    return server.close();
+  after(function (done) {
+    server.close(done);
   });
 
   it('#5199 fix excessively long replication loop', function () {
diff --git a/tests/find/test-suite-1/test.default-index.js b/tests/find/test-suite-1/test.default-index.js
index afcaaa954b..61700da0de 100644
--- a/tests/find/test-suite-1/test.default-index.js
+++ b/tests/find/test-suite-1/test.default-index.js
@@ -126,7 +126,7 @@ describe('test.default-index.js', function () {
     ]).then(function () {
       return db.find({
         selector: {foo: {$ne: "eba"}},
-        fields: ["_id",],
+        fields: ["_id"],
         sort: ["_id"]
       });
     }).then(function (resp) {
diff --git a/tests/integration/browser.migration.js b/tests/integration/browser.migration.js
index 2936a2ba60..e721649d7b 100644
--- a/tests/integration/browser.migration.js
+++ b/tests/integration/browser.migration.js
@@ -80,6 +80,12 @@ describe('migration', function () {
 
       var dbs = {};
 
+      before(function () {
+        if (usingIndexeddb() && !versionGte(scenario, '7.2.1')) {
+          return this.skip();
+        }
+      });
+
       beforeEach(function (done) {
         if (skip) {
           return this.skip();
@@ -122,12 +128,6 @@ describe('migration', function () {
         testUtils.cleanup([dbs.first.local, dbs.second.local], done);
       });
 
-      before(function () {
-        if (usingIndexeddb() && !versionGte(scenario, '7.2.1')) {
-          return this.skip();
-        }
-      });
-
       var origDocs = [
         {_id: '0', a: 1, b: 1},
         {_id: '3', a: 4, b: 16},
diff --git a/tests/integration/webrunner.js b/tests/integration/webrunner.js
index 4720b5e4b2..1577c9663a 100644
--- a/tests/integration/webrunner.js
+++ b/tests/integration/webrunner.js
@@ -21,7 +21,8 @@
                   title: obj.title,
                   duration: obj.duration,
                   slow: typeof obj.slow === 'function' ? obj.slow() : undefined,
-                  fullTitle: typeof obj.fullTitle === 'function' ? obj.fullTitle() : undefined
+                  fullTitle: typeof obj.fullTitle === 'function' ? obj.fullTitle() : undefined,
+                  titlePath: typeof obj.titlePath === 'function' ? obj.titlePath() : undefined,
                 },
                 err: err && {
                   actual: err.actual,