🥂 Initial commit

tools/utils/task-debouncer.js

@@ -0,0 +1,67 @@
+/**
+ * #### TaskDebouncer
+ * 
+ * Executes a task after a certain delay, but cancels the execution if 
+ * a new task is sent before the delay expires. Also, if a task is
+ * already being executed, the new task is queued and executed after
+ * the current one finishes. It will only execute the task that was
+ * sent last.
+ */
+export class TaskDebouncer {
+    constructor(debounceDelay) {
+        this.debounceDelay = debounceDelay;
+        this.queued = undefined;
+        this.isProcessing = false;
+        this.timerId = null;
+    }
+
+    #clearQueue() {
+        this.queued = undefined;
+    }
+
+    #enqueue(executor, args) {
+        this.queued = { executor, args };
+        this.#processQueue();
+    }
+
+    #setProcessing(value) {
+        this.isProcessing = value;
+    }
+
+    async #processQueue() {
+        if (this.isProcessing || !this.queued) {
+            return;
+        }
+        const { executor, args } = this.queued;
+        this.#clearQueue();
+
+        // execute the task
+        this.#setProcessing(true);
+        await executor(...args);
+        this.#setProcessing(false);
+
+        // continue with the next task
+        this.#continue();               
+    }
+
+    #continue() {
+        if (this.queued) {
+            this.#processQueue();
+        }
+    }
+
+    /**
+     * Adds a task to the queue. If a task is already being executed,
+     * the new task is queued and executed after the current one finishes.
+     * It will only execute the task if no other task is sent before the
+     * delay expires or before the current task finishes.
+     * 
+     * IOW, it will only execute the task that was sent last.
+     */
+    add(executor, ...args) {
+        clearTimeout(this.timerId);
+        this.timerId = setTimeout(() => {
+            this.#enqueue(executor, args);
+        }, this.debounceDelay);
+    }
+}