diff --git a/.eslintignore b/.eslintignore
index 8895c4490..bc59af4ce 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -842,6 +842,9 @@ packages/lib/SyncTargetOneDrive.js.map
 packages/lib/Synchronizer.d.ts
 packages/lib/Synchronizer.js
 packages/lib/Synchronizer.js.map
+packages/lib/TaskQueue.d.ts
+packages/lib/TaskQueue.js
+packages/lib/TaskQueue.js.map
 packages/lib/commands/historyBackward.d.ts
 packages/lib/commands/historyBackward.js
 packages/lib/commands/historyBackward.js.map
@@ -1436,6 +1439,9 @@ packages/lib/services/synchronizer/synchronizer_MigrationHandler.test.js.map
 packages/lib/services/synchronizer/tools.d.ts
 packages/lib/services/synchronizer/tools.js
 packages/lib/services/synchronizer/tools.js.map
+packages/lib/services/synchronizer/uploadUtils.d.ts
+packages/lib/services/synchronizer/uploadUtils.js
+packages/lib/services/synchronizer/uploadUtils.js.map
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.d.ts
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.js
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.js.map
diff --git a/.gitignore b/.gitignore
index 0a3273521..ca459c68e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -828,6 +828,9 @@ packages/lib/SyncTargetOneDrive.js.map
 packages/lib/Synchronizer.d.ts
 packages/lib/Synchronizer.js
 packages/lib/Synchronizer.js.map
+packages/lib/TaskQueue.d.ts
+packages/lib/TaskQueue.js
+packages/lib/TaskQueue.js.map
 packages/lib/commands/historyBackward.d.ts
 packages/lib/commands/historyBackward.js
 packages/lib/commands/historyBackward.js.map
@@ -1422,6 +1425,9 @@ packages/lib/services/synchronizer/synchronizer_MigrationHandler.test.js.map
 packages/lib/services/synchronizer/tools.d.ts
 packages/lib/services/synchronizer/tools.js
 packages/lib/services/synchronizer/tools.js.map
+packages/lib/services/synchronizer/uploadUtils.d.ts
+packages/lib/services/synchronizer/uploadUtils.js
+packages/lib/services/synchronizer/uploadUtils.js.map
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.d.ts
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.js
 packages/lib/services/synchronizer/utils/handleSyncStartupOperation.js.map
diff --git a/packages/lib/Synchronizer.ts b/packages/lib/Synchronizer.ts
index a8dd1fa41..59e138e75 100644
--- a/packages/lib/Synchronizer.ts
+++ b/packages/lib/Synchronizer.ts
@@ -18,8 +18,8 @@ import ResourceService from './services/ResourceService';
 import EncryptionService from './services/EncryptionService';
 import JoplinError from './JoplinError';
 import ShareService from './services/share/ShareService';
+import TaskQueue from './TaskQueue';
 const { sprintf } = require('sprintf-js');
-const TaskQueue = require('./TaskQueue');
 const { Dirnames } = require('./services/synchronizer/utils/types');
 
 interface RemoteItem {
@@ -564,14 +564,15 @@ export default class Synchronizer {
 								try {
 									const remoteContentPath = resourceRemotePath(local.id);
 									const result = await Resource.fullPathForSyncUpload(local);
-									local = result.resource;
+									const resource = result.resource;
+									local = resource as any;
 									const localResourceContentPath = result.path;
 
-									if (local.size >= 10 * 1000 * 1000) {
-										this.logger().warn(`Uploading a large resource (resourceId: ${local.id}, size:${local.size} bytes) which may tie up the sync process.`);
+									if (resource.size >= 10 * 1000 * 1000) {
+										this.logger().warn(`Uploading a large resource (resourceId: ${local.id}, size:${resource.size} bytes) which may tie up the sync process.`);
 									}
 
-									await this.apiCall('put', remoteContentPath, null, { path: localResourceContentPath, source: 'file', shareId: local.share_id });
+									await this.apiCall('put', remoteContentPath, null, { path: localResourceContentPath, source: 'file', shareId: resource.share_id });
 								} catch (error) {
 									if (isCannotSyncError(error)) {
 										await handleCannotSyncItem(ItemClass, syncTargetId, local, error.message);
@@ -787,7 +788,7 @@ export default class Synchronizer {
 						if (!BaseItem.isSystemPath(remote.path)) continue; // The delta API might return things like the .sync, .resource or the root folder
 
 						const loadContent = async () => {
-							const task = await this.downloadQueue_.waitForResult(path); // await this.apiCall('get', path);
+							const task = await this.downloadQueue_.waitForResult(path);
 							if (task.error) throw task.error;
 							if (!task.result) return null;
 							return await BaseItem.unserialize(task.result);
diff --git a/packages/lib/TaskQueue.test.js b/packages/lib/TaskQueue.test.js
index 0912e1855..5f4978255 100644
--- a/packages/lib/TaskQueue.test.js
+++ b/packages/lib/TaskQueue.test.js
@@ -1,5 +1,5 @@
 const { setupDatabaseAndSynchronizer, sleep, switchClient } = require('./testing/test-utils.js');
-const TaskQueue = require('./TaskQueue.js');
+const TaskQueue = require('./TaskQueue').default;
 
 describe('TaskQueue', function() {
 
diff --git a/packages/lib/TaskQueue.js b/packages/lib/TaskQueue.ts
similarity index 57%
rename from packages/lib/TaskQueue.js
rename to packages/lib/TaskQueue.ts
index f452030ba..45c660232 100644
--- a/packages/lib/TaskQueue.js
+++ b/packages/lib/TaskQueue.ts
@@ -1,23 +1,38 @@
-const time = require('./time').default;
-const Setting = require('./models/Setting').default;
-const Logger = require('./Logger').default;
+import time from './time';
+import Setting from './models/Setting';
+import Logger from './Logger';
 
-class TaskQueue {
-	constructor(name) {
-		this.waitingTasks_ = [];
-		this.processingTasks_ = {};
-		this.processingQueue_ = false;
-		this.stopping_ = false;
-		this.results_ = {};
+interface Task {
+	id: string;
+	callback: Function;
+}
+
+interface TaskResult {
+	id: string;
+	result: any;
+	error?: Error;
+}
+
+export default class TaskQueue {
+
+	private waitingTasks_: Task[] = [];
+	private processingTasks_: Record<string, Task> = {};
+	private processingQueue_ = false;
+	private stopping_ = false;
+	private results_: Record<string, TaskResult> = {};
+	private name_: string;
+	private logger_: Logger;
+
+	constructor(name: string, logger: Logger = null) {
 		this.name_ = name;
-		this.logger_ = new Logger();
+		this.logger_ = logger ? logger : new Logger();
 	}
 
 	concurrency() {
 		return Setting.value('sync.maxConcurrentConnections');
 	}
 
-	push(id, callback) {
+	push(id: string, callback: Function) {
 		if (this.stopping_) throw new Error('Cannot push task when queue is stopping');
 
 		this.waitingTasks_.push({
@@ -32,10 +47,10 @@ class TaskQueue {
 
 		this.processingQueue_ = true;
 
-		const completeTask = (task, result, error) => {
+		const completeTask = (task: Task, result: any, error: Error) => {
 			delete this.processingTasks_[task.id];
 
-			const r = {
+			const r: TaskResult = {
 				id: task.id,
 				result: result,
 			};
@@ -55,10 +70,10 @@ class TaskQueue {
 
 			task
 				.callback()
-				.then(result => {
+				.then((result: any) => {
 					completeTask(task, result, null);
 				})
-				.catch(error => {
+				.catch((error: Error) => {
 					if (!error) error = new Error('Unknown error');
 					completeTask(task, null, error);
 				});
@@ -67,29 +82,42 @@ class TaskQueue {
 		this.processingQueue_ = false;
 	}
 
-	isWaiting(taskId) {
+	isWaiting(taskId: string) {
 		return this.waitingTasks_.find(task => task.id === taskId);
 	}
 
-	isProcessing(taskId) {
+	isProcessing(taskId: string) {
 		return taskId in this.processingTasks_;
 	}
 
-	isDone(taskId) {
+	isDone(taskId: string) {
 		return taskId in this.results_;
 	}
 
-	async waitForResult(taskId) {
-		if (!this.isWaiting(taskId) && !this.isProcessing(taskId) && !this.isDone(taskId)) throw new Error(`No such task: ${taskId}`);
+	async waitForAll() {
+		return new Promise((resolve) => {
+			const checkIID = setInterval(() => {
+				if (this.waitingTasks_.length) return;
+				if (this.processingTasks_.length) return;
+				clearInterval(checkIID);
+				resolve(null);
+			}, 100);
+		});
+	}
+
+	taskExists(taskId: string) {
+		return this.isWaiting(taskId) || this.isProcessing(taskId) || this.isDone(taskId);
+	}
+
+	taskResult(taskId: string) {
+		if (!this.taskExists(taskId)) throw new Error(`No such task: ${taskId}`);
+		return this.results_[taskId];
+	}
+
+	async waitForResult(taskId: string) {
+		if (!this.taskExists(taskId)) throw new Error(`No such task: ${taskId}`);
 
 		while (true) {
-			// if (this.stopping_) {
-			// 	return {
-			// 		id: taskId,
-			// 		error: new JoplinError('Queue has been destroyed', 'destroyedQueue'),
-			// 	};
-			// }
-
 			const task = this.results_[taskId];
 			if (task) return task;
 			await time.sleep(0.1);
@@ -120,7 +148,3 @@ class TaskQueue {
 		return this.stopping_;
 	}
 }
-
-TaskQueue.CONCURRENCY = 5;
-
-module.exports = TaskQueue;
diff --git a/packages/lib/models/BaseItem.ts b/packages/lib/models/BaseItem.ts
index 56fcfdd12..e29626c8a 100644
--- a/packages/lib/models/BaseItem.ts
+++ b/packages/lib/models/BaseItem.ts
@@ -18,9 +18,17 @@ export interface ItemsThatNeedDecryptionResult {
 	items: any[];
 }
 
+export interface ItemThatNeedSync {
+	id: string;
+	sync_time: number;
+	type_: ModelType;
+	updated_time: number;
+	encryption_applied: number;
+}
+
 export interface ItemsThatNeedSyncResult {
 	hasMore: boolean;
-	items: any[];
+	items: ItemThatNeedSync[];
 	neverSyncedItemIds: string[];
 }