diff --git a/spec/integ/matrix-client-retrying.spec.js b/spec/integ/matrix-client-retrying.spec.js
index fa13384c4..c45d9ced1 100644
--- a/spec/integ/matrix-client-retrying.spec.js
+++ b/spec/integ/matrix-client-retrying.spec.js
@@ -90,7 +90,7 @@ describe("MatrixClient retrying", function() {
         // wait for the localecho of ev1 to be updated
         const p3 = new Promise((resolve, reject) => {
             room.on("Room.localEchoUpdated", (ev0) => {
-                if(ev0 === ev1) {
+                if (ev0 === ev1) {
                     resolve();
                 }
             });
diff --git a/spec/unit/room.spec.js b/spec/unit/room.spec.js
index 2f3a5b829..07ca585f1 100644
--- a/spec/unit/room.spec.js
+++ b/spec/unit/room.spec.js
@@ -1379,7 +1379,7 @@ describe("Room", function() {
             let hasThrown = false;
             try {
                 await room.loadMembersIfNeeded();
-            } catch(err) {
+            } catch (err) {
                 hasThrown = true;
             }
             expect(hasThrown).toEqual(true);
diff --git a/spec/unit/scheduler.spec.js b/spec/unit/scheduler.spec.js
index ffe9fa180..b4e83c4ef 100644
--- a/spec/unit/scheduler.spec.js
+++ b/spec/unit/scheduler.spec.js
@@ -143,7 +143,7 @@ describe("MatrixScheduler", function() {
         deferA.reject({});
         try {
             await globalA;
-        } catch(err) {
+        } catch (err) {
             await Promise.resolve();
             expect(procCount).toEqual(2);
         }
diff --git a/src/browser-index.js b/src/browser-index.js
index c1146ae13..dfa3f4d68 100644
--- a/src/browser-index.js
+++ b/src/browser-index.js
@@ -34,7 +34,7 @@ matrixcs.request(function(opts, fn) {
 let indexedDB;
 try {
     indexedDB = global.indexedDB;
-} catch(e) {}
+} catch (e) {}
 
 // if our browser (appears to) support indexeddb, use an indexeddb crypto store.
 if (indexedDB) {
diff --git a/src/client.js b/src/client.js
index 54aa73117..e3b6706c2 100644
--- a/src/client.js
+++ b/src/client.js
@@ -1925,7 +1925,7 @@ MatrixClient.prototype._restoreKeyBackup = function(
     let backupPubKey;
     try {
         backupPubKey = decryption.init_with_private_key(privKey);
-    } catch(e) {
+    } catch (e) {
         decryption.free();
         throw e;
     }
@@ -3797,7 +3797,7 @@ MatrixClient.prototype.paginateEventTimeline = function(eventTimeline, opts) {
         return pendingRequest;
     }
 
-    let path, params, promise;
+    let path; let params; let promise;
     const self = this;
 
     if (isNotifTimeline) {
@@ -4217,7 +4217,7 @@ MatrixClient.prototype.getRoomPushRule = function(scope, roomId) {
  */
 MatrixClient.prototype.setRoomMutePushRule = function(scope, roomId, mute) {
     const self = this;
-    let deferred, hasDontNotifyRule;
+    let deferred; let hasDontNotifyRule;
 
     // Get the existing room-kind push rule if any
     const roomPushRule = this.getRoomPushRule(scope, roomId);
diff --git a/src/crypto/index.js b/src/crypto/index.js
index caaaba5e4..a91c6f35a 100644
--- a/src/crypto/index.js
+++ b/src/crypto/index.js
@@ -2374,7 +2374,7 @@ Crypto.prototype.setRoomEncryption = async function(roomId, config, inhibitDevic
     // after all the in-memory state (_roomEncryptors and _roomList) has been updated
     // to avoid races when calling this method multiple times. Hence keep a hold of the promise.
     let storeConfigPromise = null;
-    if(!existingConfig) {
+    if (!existingConfig) {
         storeConfigPromise = this._roomList.setRoomEncryption(roomId, config);
     }
 
@@ -2407,7 +2407,7 @@ Crypto.prototype.setRoomEncryption = async function(roomId, config, inhibitDevic
         // which is never used (inside riot at least)
         // but didn't want to remove it as it technically would
         // be a breaking change.
-        if(!this.inhibitDeviceQuery) {
+        if (!this.inhibitDeviceQuery) {
             this._deviceList.refreshOutdatedDeviceLists();
         }
     } else {
diff --git a/src/crypto/store/indexeddb-crypto-store-backend.js b/src/crypto/store/indexeddb-crypto-store-backend.js
index 7576e9332..505e5fe51 100644
--- a/src/crypto/store/indexeddb-crypto-store-backend.js
+++ b/src/crypto/store/indexeddb-crypto-store-backend.js
@@ -131,7 +131,7 @@ export class Backend {
 
         cursorReq.onsuccess = (ev) => {
             const cursor = ev.target.result;
-            if(!cursor) {
+            if (!cursor) {
                 // no match found
                 callback(null);
                 return;
diff --git a/src/crypto/verification/SAS.js b/src/crypto/verification/SAS.js
index 7aba7622b..c69f9f7e8 100644
--- a/src/crypto/verification/SAS.js
+++ b/src/crypto/verification/SAS.js
@@ -430,7 +430,7 @@ export class SAS extends Base {
                         try {
                             await this._sendMAC(olmSAS, macMethod);
                             resolve();
-                        } catch(err) {
+                        } catch (err) {
                             reject(err);
                         }
                     },
diff --git a/src/http-api.js b/src/http-api.js
index e7134bb59..94a0dcd81 100644
--- a/src/http-api.js
+++ b/src/http-api.js
@@ -890,7 +890,7 @@ function getResponseContentType(response) {
 
     try {
         return parseContentType(contentType);
-    } catch(e) {
+    } catch (e) {
         throw new Error(`Error parsing Content-Type '${contentType}': ${e}`);
     }
 }
diff --git a/src/models/event-timeline-set.js b/src/models/event-timeline-set.js
index b681b66b8..8a76e84a2 100644
--- a/src/models/event-timeline-set.js
+++ b/src/models/event-timeline-set.js
@@ -647,7 +647,7 @@ EventTimelineSet.prototype.compareEventOrdering = function(eventId1, eventId2) {
     if (timeline1 === timeline2) {
         // both events are in the same timeline - figure out their
         // relative indices
-        let idx1, idx2;
+        let idx1; let idx2;
         const events = timeline1.getEvents();
         for (let idx = 0; idx < events.length &&
              (idx1 === undefined || idx2 === undefined); idx++) {
diff --git a/src/models/room-member.js b/src/models/room-member.js
index 4dc973c79..bb7ba9a11 100644
--- a/src/models/room-member.js
+++ b/src/models/room-member.js
@@ -286,9 +286,9 @@ RoomMember.prototype.getAvatarUrl =
  * @return {string} the mxc avatar url
  */
 RoomMember.prototype.getMxcAvatarUrl = function() {
-    if(this.events.member) {
+    if (this.events.member) {
         return this.events.member.getDirectionalContent().avatar_url;
-    } else if(this.user) {
+    } else if (this.user) {
         return this.user.avatarUrl;
     }
     return null;
diff --git a/src/models/room-state.js b/src/models/room-state.js
index 0c542432d..9bb733ba5 100644
--- a/src/models/room-state.js
+++ b/src/models/room-state.js
@@ -673,7 +673,7 @@ RoomState.prototype._maySendEventOfType = function(eventType, userId, state) {
         const userPowerLevel = power_levels.users && power_levels.users[userId];
         if (Number.isFinite(userPowerLevel)) {
             powerLevel = userPowerLevel;
-        } else if(Number.isFinite(power_levels.users_default)) {
+        } else if (Number.isFinite(power_levels.users_default)) {
             powerLevel = power_levels.users_default;
         }
 
diff --git a/src/models/room.js b/src/models/room.js
index 4a656712f..53df39899 100644
--- a/src/models/room.js
+++ b/src/models/room.js
@@ -1904,14 +1904,14 @@ function calculateRoomName(room, userId, ignoreRoomNameEvent) {
     // let's try to figure out who was here before
     let leftNames = otherNames;
     // if we didn't have heroes, try finding them in the room state
-    if(!leftNames.length) {
+    if (!leftNames.length) {
         leftNames = room.currentState.getMembers().filter((m) => {
             return m.userId !== userId &&
                 m.membership !== "invite" &&
                 m.membership !== "join";
         }).map((m) => m.name);
     }
-    if(leftNames.length) {
+    if (leftNames.length) {
         return `Empty room (was ${memberNamesToRoomName(leftNames)})`;
     } else {
         return "Empty room";
diff --git a/src/realtime-callbacks.js b/src/realtime-callbacks.js
index 0d21e23fb..2aae397ae 100644
--- a/src/realtime-callbacks.js
+++ b/src/realtime-callbacks.js
@@ -185,8 +185,8 @@ function _runCallbacks() {
  */
 function binarySearch(array, func) {
     // min is inclusive, max exclusive.
-    let min = 0,
-        max = array.length;
+    let min = 0;
+        let max = array.length;
 
     while (min < max) {
         const mid = (min + max) >> 1;
diff --git a/src/sync.js b/src/sync.js
index 015144a42..a06639790 100644
--- a/src/sync.js
+++ b/src/sync.js
@@ -701,7 +701,7 @@ SyncApi.prototype._syncFromCache = async function(savedSync) {
 
     try {
         await this._processSyncResponse(syncEventData, data);
-    } catch(e) {
+    } catch (e) {
         logger.error("Error processing cached sync", e.stack || e);
     }
 
@@ -774,7 +774,7 @@ SyncApi.prototype._sync = async function(syncOptions) {
 
     try {
         await this._processSyncResponse(syncEventData, data);
-    } catch(e) {
+    } catch (e) {
         // log the exception with stack if we have it, else fall back
         // to the plain description
         logger.error("Caught /sync error", e.stack || e);
@@ -894,7 +894,7 @@ SyncApi.prototype._onSyncError = function(err, syncOptions) {
     logger.error("/sync error %s", err);
     logger.error(err);
 
-    if(this._shouldAbortSync(err)) {
+    if (this._shouldAbortSync(err)) {
         return;
     }
 
diff --git a/src/timeline-window.js b/src/timeline-window.js
index d277b72e3..38d0c1675 100644
--- a/src/timeline-window.js
+++ b/src/timeline-window.js
@@ -396,7 +396,7 @@ TimelineWindow.prototype.getEvents = function() {
         // (Note that both this._start.index and this._end.index are relative
         // to their respective timelines' BaseIndex).
         //
-        let startIndex = 0, endIndex = events.length;
+        let startIndex = 0; let endIndex = events.length;
         if (timeline === this._start.timeline) {
             startIndex = this._start.index + timeline.getBaseIndex();
         }
diff --git a/src/webrtc/call.js b/src/webrtc/call.js
index 36db7ab46..3a2aaf757 100644
--- a/src/webrtc/call.js
+++ b/src/webrtc/call.js
@@ -176,7 +176,7 @@ MatrixCall.prototype.placeScreenSharingCall =
         debuglog("Got screen stream, requesting audio stream...");
         const audioConstraints = _getUserMediaVideoContraints('voice');
         _placeCallWithConstraints(self, audioConstraints);
-    } catch(err) {
+    } catch (err) {
         self.emit("error",
             callError(
                 MatrixCall.ERR_NO_USER_MEDIA,