*Use once, not on

src/index.js

@@ -31,11 +31,11 @@ module.exports = function createTaskQueue(options) {
 	let counters = {};
 	let starts = {};
 	let running = {};
-	
+
 	function tryRunTask(type) {
 		let maxTasks = defaultValue(taskOptions[type].concurrency, Infinity);
 		let waitTime = remainingInterval(type);
-		
+
 		if (tasks[type].length > 0) {
 			if (waitTime <= 0) {
 				if (counters[type] < maxTasks) {
@@ -43,7 +43,7 @@ module.exports = function createTaskQueue(options) {
 						debugLoop(`Queue for '${type}' is now running`);
 						markQueueRunning(type);
 					}
-					
+
 					runTask(type);
 				} else {
 					debugLoop(`Reached concurrency for '${type}'`);
@@ -52,7 +52,7 @@ module.exports = function createTaskQueue(options) {
 			} else {
 				debugLoop(`Registering queue delay for '${type}'`);
 				taskQueue.emit(`delayed:${type}`);
-				
+
 				setTimeout(() => {
 					tryRunTask(type);
 				}, waitTime);
@@ -64,19 +64,19 @@ module.exports = function createTaskQueue(options) {
 			}
 		}
 	}
-	
+
 	function remainingInterval(type) {
 		let taskInterval = defaultValue(taskOptions[type].interval, 0) * 1000;
 		let lastTask = defaultValue(starts[type], 0);
-		
+
 		return (lastTask + taskInterval) - Date.now();
 	}
-	
+
 	function runTask(type) {
 		let task = tasks[type].shift();
-		
+
 		markStarted(type, task);
-		
+
 		Promise.try(() => {
 			return handlers[type](task.data);
 		}).then((result) => {
@@ -89,45 +89,45 @@ module.exports = function createTaskQueue(options) {
 			tryRunTask(type);
 		});
 	}
-	
+
 	function markStarted(type, task) {
 		debugTasks(`markStarted (${type}): ${debugObject(task.data)}`);
 		counters[type] += 1;
 		starts[type] = Date.now();
 		taskQueue.emit(`started:${type}`, task.data);
 	}
-	
+
 	function markFinished(type, task) {
 		debugTasks(`markFinished (${type}): ${debugObject(task.data)}`);
 		counters[type] -= 1;
 		taskQueue.emit(`finished:${type}`, task.data);
 		checkCompletion(type);
 	}
-	
+
 	function markSuccess(type, task) {
 		debugTasks(`markSuccess (${type}): ${debugObject(task.data)}`);
 		markFinished(type, task);
 		taskQueue.emit(`success:${type}`, task.data);
 	}
-	
+
 	function markFailed(type, task) {
 		debugTasks(`markFailed (${type}): ${debugObject(task.data)}`);
 		markFinished(type, task);
 		taskQueue.emit(`failed:${type}`, task.data);
 	}
-	
+
 	function markQueueRunning(type) {
 		debugLoop(`markQueueRunning (${type})`);
 		taskQueue.emit(`queueRunning:${type}`);
 		running[type] = true;
 	}
-	
+
 	function markQueueDrained(type) {
 		debugLoop(`markQueueDrained (${type})`);
 		taskQueue.emit(`queueDrained:${type}`);
 		running[type] = false;
 	}
-	
+
 	function markQueueCompleted(type) {
 		debugLoop(`markQueueCompleted (${type})`);
 		taskQueue.emit(`queueCompleted:${type}`);
@@ -156,7 +156,7 @@ module.exports = function createTaskQueue(options) {
 				if (handlers[type] == null) {
 					throw new TaskQueueError("No such task type exists.")
 				}
-				
+
 				debugTasks(`Queueing new task for '${type}': ${debugObject(data)}`);
 
 				let resolveFunc, rejectFunc;
@@ -170,9 +170,9 @@ module.exports = function createTaskQueue(options) {
 					resolve: resolveFunc,
 					reject: rejectFunc
 				});
-				
+
 				tryRunTask(type);
-				
+
 				return deferredPromise;
 			})
 		},
@@ -198,7 +198,7 @@ module.exports = function createTaskQueue(options) {
 				} else {
 					debugLoop(`Returning awaitDrained Promise for '${type}'`);
 					return new Promise((resolve, reject) => {
-						this.on(`queueDrained:${type}`, () => {
+						this.once(`queueDrained:${type}`, () => {
 							debugLoop(`Resolving awaitDrained Promise for '${type}'`);
 							resolve();
 						})
@@ -220,7 +220,7 @@ module.exports = function createTaskQueue(options) {
 				} else {
 					debugLoop(`Returning awaitCompleted Promise for '${type}'`);
 					return new Promise((resolve, reject) => {
-						this.on(`queueCompleted:${type}`, () => {
+						this.once(`queueCompleted:${type}`, () => {
 							debugLoop(`Resolving awaitCompleted Promise for '${type}'`);
 							resolve();
 						})
@@ -229,6 +229,6 @@ module.exports = function createTaskQueue(options) {
 			})
 		}
 	});
-	
+
 	return taskQueue;
 }