initial implementation

app/queue.ts

@@ -0,0 +1,44 @@
+interface QueueItem<T> {
+	value: T
+	behind: QueueItem<T> | null
+}
+
+class Queue<T> {
+	private front: QueueItem<T> | null = null
+	private back: QueueItem<T> | null = null
+	private length = 0
+
+	get isEmpty() {
+		return this.length === 0
+	}
+
+	enqueue(value: T) {
+		const item: QueueItem<T> = {
+			value,
+			behind: null,
+		}
+		if (!this.front && !this.back) {
+			this.front = item
+			this.back = item
+		} else {
+			this.back!.behind = item
+			this.back = item
+		}
+		this.length++
+	}
+
+	dequeue(): T | null {
+		if (this.front) {
+			const value = this.front.value
+			this.front = this.front.behind
+			if (--this.length === 0) {
+				this.front = null
+				this.back = null
+			}
+			return value
+		}
+		return null
+	}
+}
+
+export { Queue }