Merge pull request #117 from vector-im/bwindels/idb-promises

Prevent transaction from closing on IE11/Win7
2024-12-23 03:25:12 +01:00 · 2020-09-28 13:37:34 +00:00 · 2020-09-28 13:37:34 +00:00 · 3440823981
commit 3440823981
parent 255559460e 47dbc87e95
11 changed files with 655 additions and 11 deletions
--- a/package.json
+++ b/package.json
@ -47,6 +47,7 @@
    "xxhashjs": "^0.2.2"
  },
  "dependencies": {
+    "es6-promise": "https://github.com/bwindels/es6-promise.git#bwindels/expose-flush",
    "aes-js": "^3.1.2",
    "another-json": "^0.2.0",
    "base64-arraybuffer": "^0.2.0",
--- a/prototypes/idb-promises.html
+++ b/prototypes/idb-promises.html
@ -0,0 +1,118 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+</head>
+<body>
+    <script type="text/javascript" src="promifill.js"></script>
+    <!-- <script src="https://cdn.jsdelivr.net/npm/promise-polyfill@8/dist/polyfill.min.js"></script> -->
+    <script type="text/javascript">
+        //window.Promise = Promifill;
+        function reqAsPromise(req) {
+            return new Promise(function (resolve, reject) {
+                req.onsuccess = function() {
+                    resolve(req);
+                    Promise.flushQueue && Promise.flushQueue();
+                };
+                req.onerror = function(e) {
+                    reject(new Error("IDB request failed: " + e.target.error.message));
+                    Promise.flushQueue && Promise.flushQueue();
+                };
+            });
+        }
+
+        function Storage(databaseName) {
+            this._databaseName = databaseName;
+            this._database = null;
+        }
+
+        Storage.prototype = {
+            open: function() {
+                const req = window.indexedDB.open(this._databaseName);
+                const self = this;
+                req.onupgradeneeded = function(ev) {
+                    const db = ev.target.result;
+                    const oldVersion = ev.oldVersion;
+                    self._createStores(db, oldVersion);
+                }; 
+                return reqAsPromise(req).then(function() {
+                    self._database = req.result;
+                });
+            },
+            openTxn: function(mode, storeName) {
+                const txn = this._database.transaction([storeName], mode);
+                const store = txn.objectStore(storeName);
+                return Promise.resolve(store);
+            },
+            _createStores: function(db) {
+                db.createObjectStore("foos", {keyPath: ["id"]});
+            }
+        };
+
+        function getAll(store) {
+            const request = store.openCursor();
+            const results = [];
+            return new Promise(function(resolve, reject) {
+                request.onsuccess = function(event) {
+                    const cursor = event.target.result;
+                    if(cursor) {
+                        results.push(cursor.value);
+                        cursor.continue();
+                    } else {
+                        resolve(results);
+                        Promise.flushQueue && Promise.flushQueue();
+                    }
+                };
+                request.onerror = function(e) {
+                    reject(new Error("IDB request failed: " + e.target.error.message));
+                    Promise.flushQueue && Promise.flushQueue();
+                };
+            });
+        }
+
+        function main() {
+            let storage = new Storage("idb-promises");
+            let store;
+            storage.open().then(function() {
+                return storage.openTxn("readwrite", "foos");
+            }).then(function(s) {
+                store = s;
+                store.clear();
+                store.add({id: 5, name: "foo"});
+                store.add({id: 6, name: "bar"});
+                return getAll(store);
+            }).then(function(all) {
+                console.log("all1", all);
+                store.add({id: 7, name: "bazzz"});
+                return getAll(store);
+            }).then(function(all) {
+                console.log("all2", all);
+            }).catch(function(err) {
+                console.error(err.message + ": " + err.stack);
+            });
+        }
+        main();
+
+
+        /*
+        
+        we basically want something like this for IE11/Win7:
+            
+            return new Promise(function (resolve, reject) {
+                req.onsuccess = function() {
+                    resolve(req);
+                    Promise?.flushQueue();
+                };
+                req.onerror = function(e) {
+                    reject(new Error("IDB request failed: " + e.target.error.message));
+                    Promise?.flushQueue();
+                };
+            });
+
+        we don't have this problem on platforms with a native promise implementation, so we can just have our own (forked) promise polyfill? 
+         */
+    </script>
+</body>
+</html>
+ 
--- a/prototypes/promifill.js
+++ b/prototypes/promifill.js
@ -0,0 +1,444 @@
+"use strict";
+
+function _createForOfIteratorHelper(o, allowArrayLike) { var it; if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) { if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") { if (it) o = it; var i = 0; var F = function F() {}; return { s: F, n: function n() { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }, e: function e(_e) { throw _e; }, f: F }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } var normalCompletion = true, didErr = false, err; return { s: function s() { it = o[Symbol.iterator](); }, n: function n() { var step = it.next(); normalCompletion = step.done; return step; }, e: function e(_e2) { didErr = true; err = _e2; }, f: function f() { try { if (!normalCompletion && it.return != null) it.return(); } finally { if (didErr) throw err; } } }; }
+
+function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
+
+function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }
+
+function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }
+
+var PENDING = void 0,
+    FULFILLED = true,
+    REJECTED = false;
+
+var Promifill = /*#__PURE__*/function () {
+  _createClass(Promifill, [{
+    key: "state",
+    get: function get() {
+      return PENDING;
+    }
+  }, {
+    key: "value",
+    get: function get() {
+      return void 0;
+    }
+  }, {
+    key: "settled",
+    get: function get() {
+      return false;
+    }
+  }]);
+
+  function Promifill(executor) {
+    var _this = this;
+
+    _classCallCheck(this, Promifill);
+
+    if (typeof executor != "function") {
+      throw new TypeError("Promise resolver ".concat(Object.prototype.toString.call(executor), " is not a function"));
+    }
+
+    defineProperty(this, "chain", []);
+    defineProperty(this, "observers", []);
+    var secret = [];
+
+    var resolve = function resolve(value, bypassKey) {
+      if (_this.settled && bypassKey !== secret) {
+        return;
+      }
+
+      defineProperty(_this, "settled", true);
+      var then_ = value && value.then;
+      var thenable = typeof then_ == "function";
+
+      if (thenable) {
+        defineProperty(value, "preventThrow", true);
+      }
+
+      if (thenable && value.state === PENDING) {
+        then_.call(value, function (v) {
+          return resolve(v, secret);
+        }, function (r) {
+          return reject(r, secret);
+        });
+      } else {
+        defineProperty(_this, "value", thenable ? value.value : value);
+        defineProperty(_this, "state", thenable ? value.state : FULFILLED);
+        schedule(_this.observers.map(function (observer) {
+          return {
+            handler: _this.state === FULFILLED ? observer.onfulfill : observer.onreject,
+            value: _this.value
+          };
+        }));
+
+        if (_this.state === REJECTED) {
+          raiseUnhandledPromiseRejectionException(_this.value, _this);
+        }
+      }
+    };
+
+    var reject = function reject(reason, bypassKey) {
+      if (_this.settled && bypassKey !== secret) {
+        return;
+      }
+
+      defineProperty(_this, "settled", true);
+      defineProperty(_this, "value", reason);
+      defineProperty(_this, "state", REJECTED);
+      schedule(_this.observers.map(function (observer) {
+        return {
+          handler: observer.onreject,
+          value: _this.value
+        };
+      }));
+      raiseUnhandledPromiseRejectionException(_this.value, _this);
+    };
+
+    try {
+      executor(resolve, reject);
+    } catch (error) {
+      reject(error);
+    }
+  }
+
+  _createClass(Promifill, [{
+    key: "then",
+    value: function then(onfulfill, onreject) {
+      var _this2 = this;
+
+      var chainedPromise = new this.constructor(function (resolve, reject) {
+        var internalOnfulfill = function internalOnfulfill(value) {
+          try {
+            resolve(typeof onfulfill == "function" ? onfulfill(value) : value);
+          } catch (error) {
+            reject(error);
+          }
+        };
+
+        var internalOnreject = function internalOnreject(reason) {
+          try {
+            if (typeof onreject == "function") {
+              resolve(onreject(reason));
+            } else {
+              reject(reason);
+            }
+          } catch (error) {
+            reject(error);
+          }
+        };
+
+        if (_this2.state === PENDING) {
+          _this2.observers.push({
+            onfulfill: internalOnfulfill,
+            onreject: internalOnreject
+          });
+        } else {
+          schedule([{
+            handler: _this2.state === FULFILLED ? internalOnfulfill : internalOnreject,
+            value: _this2.value
+          }]);
+        }
+      });
+      this.chain.push(chainedPromise);
+      return chainedPromise;
+    }
+  }, {
+    key: "catch",
+    value: function _catch(onreject) {
+      return this.then(null, onreject);
+    }
+  }, {
+    key: "finally",
+    value: function _finally(oncomplete) {
+      var _this3 = this;
+
+      var chainedPromise = new this.constructor(function (resolve, reject) {
+        var internalOncomplete = function internalOncomplete() {
+          try {
+            oncomplete();
+
+            if (_this3.state === FULFILLED) {
+              resolve(_this3.value);
+            } else {
+              reject(_this3.value);
+            }
+          } catch (error) {
+            reject(error);
+          }
+        };
+
+        if (_this3.state === PENDING) {
+          _this3.observers.push({
+            onfulfill: internalOncomplete,
+            onreject: internalOncomplete
+          });
+        } else {
+          schedule([{
+            handler: internalOncomplete
+          }]);
+        }
+      });
+      this.chain.push(chainedPromise);
+      return chainedPromise;
+    }
+  }], [{
+    key: "resolve",
+    value: function resolve(value) {
+      return value && value.constructor === Promifill ? value : new Promifill(function (resolve) {
+        resolve(value);
+      });
+    }
+  }, {
+    key: "reject",
+    value: function reject(reason) {
+      return new Promifill(function (_, reject) {
+        reject(reason);
+      });
+    }
+  }, {
+    key: "all",
+    value: function all(iterable) {
+      return new Promifill(function (resolve, reject) {
+        validateIterable(iterable);
+        var iterableSize = 0;
+        var values = [];
+
+        if (isEmptyIterable(iterable)) {
+          return resolve(values);
+        }
+
+        var add = function add(value, index) {
+          values[index] = value;
+
+          if (values.filter(function () {
+            return true;
+          }).length === iterableSize) {
+            resolve(values);
+          }
+        };
+
+        var _iterator = _createForOfIteratorHelper(iterable),
+            _step;
+
+        try {
+          for (_iterator.s(); !(_step = _iterator.n()).done;) {
+            var item = _step.value;
+
+            (function (entry, index) {
+              Promifill.resolve(entry).then(function (value) {
+                return add(value, index);
+              }, reject);
+            })(item, iterableSize++);
+          }
+        } catch (err) {
+          _iterator.e(err);
+        } finally {
+          _iterator.f();
+        }
+      });
+    }
+  }, {
+    key: "race",
+    value: function race(iterable) {
+      return new Promifill(function (resolve, reject) {
+        validateIterable(iterable);
+
+        if (isEmptyIterable(iterable)) {
+          return;
+        }
+
+        var _iterator2 = _createForOfIteratorHelper(iterable),
+            _step2;
+
+        try {
+          for (_iterator2.s(); !(_step2 = _iterator2.n()).done;) {
+            var entry = _step2.value;
+            Promifill.resolve(entry).then(resolve, reject);
+          }
+        } catch (err) {
+          _iterator2.e(err);
+        } finally {
+          _iterator2.f();
+        }
+      });
+    }
+  }, {
+    key: "flushQueue",
+    value: function flushQueue() {
+        console.log("running promise sync by flushing queue");
+      schedule.flushQueue();
+    }
+  }]);
+
+  return Promifill;
+}();
+
+var defineProperty = function defineProperty(obj, propName, propValue) {
+  Object.defineProperty(obj, propName, {
+    value: propValue
+  });
+};
+
+var defer = function defer(handler) {
+  return function () {
+    for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+      args[_key] = arguments[_key];
+    }
+
+    setTimeout.apply(void 0, [handler, 0].concat(args));
+  };
+};
+
+var thrower = function thrower(error) {
+  throw error instanceof Error ? error : new Error(error);
+};
+
+var raiseUnhandledPromiseRejectionException = defer(function (error, promise) {
+  if (promise.preventThrow || promise.chain.length > 0) {
+    return;
+  }
+
+  thrower(error);
+});
+
+var MutationObserverStrategy = /*#__PURE__*/function () {
+  function MutationObserverStrategy(handler) {
+    _classCallCheck(this, MutationObserverStrategy);
+
+    var observer = new MutationObserver(handler);
+    var node = this.node = document.createTextNode("");
+    observer.observe(node, {
+      characterData: true
+    });
+  }
+
+  _createClass(MutationObserverStrategy, [{
+    key: "trigger",
+    value: function trigger() {
+      this.node.data = this.node.data === 1 ? 0 : 1;
+    }
+  }]);
+
+  return MutationObserverStrategy;
+}();
+
+var NextTickStrategy = /*#__PURE__*/function () {
+  function NextTickStrategy(handler) {
+    _classCallCheck(this, NextTickStrategy);
+
+    this.scheduleNextTick = function () {
+      return process.nextTick(handler);
+    };
+  }
+
+  _createClass(NextTickStrategy, [{
+    key: "trigger",
+    value: function trigger() {
+      this.scheduleNextTick();
+    }
+  }]);
+
+  return NextTickStrategy;
+}();
+
+var BetterThanNothingStrategy = /*#__PURE__*/function () {
+  function BetterThanNothingStrategy(handler) {
+    _classCallCheck(this, BetterThanNothingStrategy);
+
+    this.scheduleAsap = function () {
+      return setTimeout(handler, 0);
+    };
+  }
+
+  _createClass(BetterThanNothingStrategy, [{
+    key: "trigger",
+    value: function trigger() {
+      this.scheduleAsap();
+    }
+  }]);
+
+  return BetterThanNothingStrategy;
+}();
+
+var getStrategy = function getStrategy() {
+  if (typeof window != "undefined" && typeof window.MutationObserver == "function") {
+    return MutationObserverStrategy;
+  }
+
+  if (typeof global != "undefined" && typeof process != "undefined" && typeof process.nextTick == "function") {
+    return NextTickStrategy;
+  }
+
+  return BetterThanNothingStrategy;
+};
+
+var schedule = function () {
+  var microtasks = [];
+
+  var run = function run() {
+    var handler, value;
+
+    while (microtasks.length > 0 && (_microtasks$shift = microtasks.shift(), handler = _microtasks$shift.handler, value = _microtasks$shift.value, _microtasks$shift)) {
+      var _microtasks$shift;
+      console.log("running handler with", value);
+      handler(value);
+    }
+  };
+
+  var Strategy = getStrategy();
+  var ctrl = new Strategy(run);
+
+  var scheduleFn = function scheduleFn(observers) {
+    if (observers.length == 0) {
+      return;
+    }
+
+    microtasks = microtasks.concat(observers);
+    observers.length = 0;
+    ctrl.trigger();
+  };
+
+  scheduleFn.flushQueue = function () {
+    run();
+  };
+
+  return scheduleFn;
+}();
+
+var isIterable = function isIterable(subject) {
+  return subject != null && typeof subject[Symbol.iterator] == "function";
+};
+
+var validateIterable = function validateIterable(subject) {
+  if (isIterable(subject)) {
+    return;
+  }
+
+  throw new TypeError("Cannot read property 'Symbol(Symbol.iterator)' of ".concat(Object.prototype.toString.call(subject), "."));
+};
+
+var isEmptyIterable = function isEmptyIterable(subject) {
+  var _iterator3 = _createForOfIteratorHelper(subject),
+      _step3;
+
+  try {
+    for (_iterator3.s(); !(_step3 = _iterator3.n()).done;) {
+      var _ = _step3.value;
+      // eslint-disable-line no-unused-vars
+      return false;
+    }
+  } catch (err) {
+    _iterator3.e(err);
+  } finally {
+    _iterator3.f();
+  }
+
+  return true;
+};
+
+window.Promifill = Promifill;
--- a/scripts/build.mjs
+++ b/scripts/build.mjs
@ -221,7 +221,11 @@ async function buildJsLegacy(inputFile, outputName, extraFile, polyfillFile) {
                {
                    useBuiltIns: "entry",
                    corejs: "3",
-                    targets: "IE 11"
+                    targets: "IE 11",
+                    // we provide our own promise polyfill (es6-promise)
+                    // with support for synchronous flushing of
+                    // the queue for idb where needed 
+                    exclude: ["es.promise", "es.promise.all-settled", "es.promise.finally"]
                }
            ]
        ]
--- a/scripts/post-install.mjs
+++ b/scripts/post-install.mjs
@ -96,6 +96,15 @@ async function populateLib() {
        path.join(modulesDir, 'aes-js/index.js'),
        path.join(libDir, "aes-js/index.js")
    );
+    // es6-promise is already written as an es module,
+    // but it does need to be babelified, and current we don't babelify
+    // anything in node_modules in the build script, so make a bundle that
+    // is conveniently not placed in node_modules rather than symlinking.
+    await fs.mkdir(path.join(libDir, "es6-promise/"));
+    await commonjsToESM(
+        path.join(modulesDir, 'es6-promise/lib/es6-promise/promise.js'),
+        path.join(libDir, "es6-promise/index.js")
+    );
 }

 populateLib();
--- a/src/legacy-polyfill.js
+++ b/src/legacy-polyfill.js
@ -24,6 +24,14 @@ import "mdn-polyfills/Element.prototype.closest";
 // it will also include the file supporting *all* the encodings,
 // weighing a good extra 500kb :-(
 import "text-encoding";
+import {checkNeedsSyncPromise} from "./matrix/storage/idb/utils.js";
+import Promise from "../lib/es6-promise/index.js";
+
+if (typeof window.Promise === "undefined") {
+    window.Promise = Promise;
+    // TODO: should be awaited before opening any session in the picker
+    checkNeedsSyncPromise();
+}

 // TODO: contribute this to mdn-polyfills
 if (!Element.prototype.remove) {
--- a/src/matrix/storage/idb/StorageFactory.js
+++ b/src/matrix/storage/idb/StorageFactory.js
@ -30,7 +30,7 @@ export class StorageFactory {

    delete(sessionId) {
        const databaseName = sessionName(sessionId);
-        const req = window.indexedDB.deleteDatabase(databaseName);
+        const req = indexedDB.deleteDatabase(databaseName);
        return reqAsPromise(req);
    }

--- a/src/matrix/storage/idb/utils.js
+++ b/src/matrix/storage/idb/utils.js
@ -1,5 +1,6 @@
 /*
 Copyright 2020 Bruno Windels <bruno@windels.cloud>
+Copyright 2020 The Matrix.org Foundation C.I.C.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@ -16,7 +17,37 @@ limitations under the License.

 import { StorageError } from "../common.js";

-class WrappedDOMException extends StorageError {
+let needsSyncPromise = false;
+
+/* should be called on legacy platforms to see
+   if transactions close before draining the microtask queue (IE11 on Windows 7).
+   If this is the case, promises need to be resolved
+   synchronously from the idb request handler to prevent the transaction from closing prematurely.
+*/
+export async function checkNeedsSyncPromise() {
+    // important to have it turned off while doing the test,
+    // otherwise reqAsPromise would not fail
+    needsSyncPromise = false;
+    const NAME = "test-idb-needs-sync-promise";
+    const db = await openDatabase(NAME, db => {
+        db.createObjectStore("test", {keyPath: "key"});
+    }, 1);
+    const txn = db.transaction("test", "readonly");
+    try {
+        await reqAsPromise(txn.objectStore("test").get(1));
+        await reqAsPromise(txn.objectStore("test").get(2));
+    } catch (err) {
+        // err.name would be either TransactionInactiveError or InvalidStateError,
+        // but let's not exclude any other failure modes
+        needsSyncPromise = true;
+    }
+    // we could delete the store here, 
+    // but let's not create it on every page load on legacy platforms,
+    // and just keep it around
+    return needsSyncPromise;
+}
+
+class IDBRequestError extends StorageError {
    constructor(request) {
        const source = request?.source;
        const storeName = source?.name || "<unknown store>";
@ -38,7 +69,7 @@ export function decodeUint32(str) {
 }

 export function openDatabase(name, createObjectStore, version) {
-    const req = window.indexedDB.open(name, version);
+    const req = indexedDB.open(name, version);
    req.onupgradeneeded = (ev) => {
        const db = ev.target.result;
        const txn = ev.target.transaction;
@ -50,15 +81,27 @@ export function openDatabase(name, createObjectStore, version) {

 export function reqAsPromise(req) {
    return new Promise((resolve, reject) => {
-        req.addEventListener("success", event => resolve(event.target.result));
-        req.addEventListener("error", event => reject(new WrappedDOMException(event.target)));
+        req.addEventListener("success", event => {
+            resolve(event.target.result);
+            needsSyncPromise && Promise._flush && Promise._flush();
+        });
+        req.addEventListener("error", () => {
+            reject(new IDBRequestError(req));
+            needsSyncPromise && Promise._flush && Promise._flush();
+        });
    });
 }

 export function txnAsPromise(txn) {
    return new Promise((resolve, reject) => {
-        txn.addEventListener("complete", resolve);
-        txn.addEventListener("abort", event => reject(new WrappedDOMException(event.target)));
+        txn.addEventListener("complete", () => {
+            resolve();
+            needsSyncPromise && Promise._flush && Promise._flush();
+        });
+        txn.addEventListener("abort", () => {
+            reject(new IDBRequestError(txn));
+            needsSyncPromise && Promise._flush && Promise._flush();
+        });
    });
 }

@ -66,21 +109,25 @@ export function iterateCursor(cursorRequest, processValue) {
    // TODO: does cursor already have a value here??
    return new Promise((resolve, reject) => {
        cursorRequest.onerror = () => {
-            reject(new StorageError("Query failed", cursorRequest.error));
+            reject(new IDBRequestError(cursorRequest));
+            needsSyncPromise && Promise._flush && Promise._flush();
        };
        // collect results
        cursorRequest.onsuccess = (event) => {
            const cursor = event.target.result;
            if (!cursor) {
                resolve(false);
+                needsSyncPromise && Promise._flush && Promise._flush();
                return; // end of results
            }
            const result = processValue(cursor.value, cursor.key);
+            // TODO: don't use object for result and assume it's jumpTo when not === true/false or undefined
            const done = result?.done;
            const jumpTo = result?.jumpTo;

            if (done) {
                resolve(true);
+                needsSyncPromise && Promise._flush && Promise._flush();
            } else if(jumpTo) {
                cursor.continue(jumpTo);
            } else {
--- a/src/utils/WorkerPool.js
+++ b/src/utils/WorkerPool.js
@ -103,7 +103,9 @@ export class WorkerPool {
                    if (message.type === "success") {
                        request._resolve(message.payload);
                    } else if (message.type === "error") {
-                        request._reject(new Error(message.stack));
+                        const err = new Error(message.message);
+                        err.stack = message.stack;
+                        request._reject(err);
                    }
                    request._dispose();
                }
--- a/src/worker-polyfill.js
+++ b/src/worker-polyfill.js
@ -17,8 +17,14 @@ limitations under the License.

 // polyfills needed for IE11
 // just enough to run olm, have promises and async/await
+
+// load this first just in case anything else depends on it
+import Promise from "../lib/es6-promise/index.js";
+// not calling checkNeedsSyncPromise from here as we don't do any idb in the worker,
+// mainly because IE doesn't handle multiple concurrent connections well
+self.Promise = Promise;
+
 import "regenerator-runtime/runtime";
-import "core-js/modules/es.promise";
 import "core-js/modules/es.math.imul";
 import "core-js/modules/es.math.clz32";

@ -48,3 +54,4 @@ import "core-js/modules/es.typed-array.to-locale-string";
 import "core-js/modules/es.typed-array.to-string";
 import "core-js/modules/es.typed-array.iterator";
 import "core-js/modules/es.object.to-string";
+
--- a/yarn.lock
+++ b/yarn.lock
@ -1205,6 +1205,10 @@ entities@^2.0.0:
  resolved "https://registry.yarnpkg.com/entities/-/entities-2.0.0.tgz#68d6084cab1b079767540d80e56a39b423e4abf4"
  integrity sha512-D9f7V0JSRwIxlRI2mjMqufDrRDnx8p+eEOz7aUM9SuvF8gsBzra0/6tbjl1m8eQHrZlYj6PxqE00hZ1SAIKPLw==

+"es6-promise@https://github.com/bwindels/es6-promise.git#bwindels/expose-flush":
+  version "4.2.8"
+  resolved "https://github.com/bwindels/es6-promise.git#112f78f5829e627055b0ff56a52fecb63f6003b1"
+
 escalade@^3.0.2:
  version "3.0.2"
  resolved "https://registry.yarnpkg.com/escalade/-/escalade-3.0.2.tgz#6a580d70edb87880f22b4c91d0d56078df6962c4"