feat(Queue): Adds Queue datastructure

esmExport.js

@@ -63,6 +63,7 @@ export { default as Prompt } from './src/Utility/Discord/Prompt';
 export { default as MessageCollector } from './src/Utility/Discord/MessageCollector';
 export { default as ReactionCollector } from './src/Utility/Discord/ReactionCollector';
 // External
+export { default as Queue } from './src/Utility/External/Queue';
 export { default as FunctionQueue } from './src/Utility/External/FunctionQueue';
 export { default as AutoQueue } from './src/Utility/External/AutoQueue';
 export { default as AsyncQueue } from './src/Utility/External/AsyncQueue';

examples/djs/src/modules/Private/commands/Eval.js

@@ -12,6 +12,7 @@ import {
     Embed,
     Prompt,
     MessageCollector,
+    Queue,
     FunctionQueue,
     AutoQueue,
     AsyncQueue,

examples/eris/src/modules/Private/commands/Eval.js

@@ -12,6 +12,7 @@ import {
     Embed,
     Prompt,
     MessageCollector,
+    Queue,
     FunctionQueue,
     AutoQueue,
     AsyncQueue,

src/Utility/External/AsyncQueue.js

@@ -18,10 +18,10 @@ class AsyncQueue extends FunctionQueue {
      * @memberof AsyncQueue
      */
     async exec() {
-        if (this._functions.length > 0) {
+        if (this._functions.size > 0) {
             this._running = true;
 
-            const func = this._functions.shift();
+            const func = this._functions.dequeue();
             try {
                 await func();
             } catch (err) {
@@ -50,7 +50,7 @@ class AsyncQueue extends FunctionQueue {
     add(func, toExec = true, ...args) {
         const promise = new Promise( (resolve, reject) => {
             const fn = this.createClosure(func, resolve, reject, ...args);
-            this._functions.push(fn);
+            this._functions.queue(fn);
         } );
 
         if (toExec && !this._running) {

src/Utility/External/AutoQueue.js

@@ -18,10 +18,10 @@ class AutoQueue extends FunctionQueue {
      * @memberof AutoQueue
      */
     async exec() {
-        if (this._functions.length > 0) {
+        if (this._functions.size > 0) {
             this._running = true;
 
-            const func = this._functions.shift();
+            const func = this._functions.dequeue();
             try {
                 await func();
             } catch (err) {

src/Utility/External/FunctionQueue.js

@@ -1,3 +1,5 @@
+import Queue from './Queue';
+
 /**
  * This default FunctionQueue works in a synchronous fashion.
  * It will execute all synchronous functions sequentially.
@@ -21,7 +23,7 @@ class FunctionQueue {
         /**
          * @type {Array<Function>}
          */
-        this._functions = [];
+        this._functions = new Queue();
         this._running = false;
 
         this.stopOnError = stopOnError;
@@ -32,9 +34,9 @@ class FunctionQueue {
      * @memberof FunctionQueue
      */
     exec() {
-        if (this._functions.length > 0) {
+        if (this._functions.size > 0) {
             this._running = true;
-            const func = this._functions.shift();
+            const func = this._functions.dequeue();
 
             try {
                 func();
@@ -63,7 +65,7 @@ class FunctionQueue {
     add(func, toExec = true, ...args) {
         const fn = this.createClosure(func, ...args);
 
-        this._functions.add(fn);
+        this._functions.queue(fn);
 
         if (toExec && !this._running) {
             this.exec();

src/Utility/External/Queue.js

@@ -0,0 +1,80 @@
+/**
+ * Queue class.
+ *
+ * @author KhaaZ
+ *
+ * @template T
+ *
+ * @prop {Array<T>} _elements
+ * @prop {Boolean} max
+ * @prop {Boolean} replaceOnMax
+ *
+ * @class Queue
+ */
+class Queue {
+    /**
+     * Creates an instance of Queue.
+     *
+     * @param {Number} [max=null] - Maximum number of elements that can be added in this queue
+     * @param {Boolean} [replaceOnMax=true] - Whether to replace value when adding if max is reached (dequeue first element and queue new element)
+     * @memberof Queue
+     */
+    constructor(max = null, replaceOnMax = true) {
+        this._elements = [];
+        this.max = max;
+        this.replaceOnMax = replaceOnMax;
+    }
+
+    /**
+     * Returns the Queue size
+     *
+     * @readonly
+     * @type {Number}
+     * @memberof Queue
+     */
+    get size() {
+        return this._elements.length;
+    }
+
+    /**
+     * Return first element of this queue
+     *
+     * @returns {T}
+     * @memberof Queue
+     */
+    first() {
+        return this._elements[0];
+    }
+
+    /**
+     * Queue up an element.
+     *
+     * @param {T} elem
+     * @param {Boolean} replaceOnMax
+     * @returns {Boolean} Whether element was successfully added
+     * @memberof Queue
+     */
+    queue(elem, replaceOnMax) {
+        if (this.max && this._elements.length === this.max) {
+            if ( (replaceOnMax !== undefined) ? replaceOnMax : this.replaceOnMax) {
+                this._elements.shift();
+            } else {
+                return false;
+            }
+        }
+        this._elements.push(elem);
+        return true;
+    }
+
+    /**
+     * Dequeue an element and returns it
+     *
+     * @returns {T}
+     * @memberof Queue
+     */
+    dequeue() {
+        return this._elements.shift();
+    }
+}
+
+export default Queue;