Qortal-Hub/src/utils/queue/queue.ts

export class RequestQueueWithPromise {
	constructor(maxConcurrent = 5) {
	  this.queue = [];
	  this.maxConcurrent = maxConcurrent;
	  this.currentlyProcessing = 0;
	  this.isPaused = false; // Flag to track whether the queue is paused
	}
  
	// Add a request to the queue and return a promise
	enqueue(request) {
	  return new Promise((resolve, reject) => {
		// Push the request and its resolve and reject callbacks to the queue
		this.queue.push({ request, resolve, reject });
		this.process();
	  });
	}
  
	// Process requests in the queue
	async process() {
	  // Process requests only if the queue is not paused
	  if (this.isPaused) return;
  
	  while (this.queue.length > 0 && this.currentlyProcessing < this.maxConcurrent) {
		this.currentlyProcessing++;
  
		const { request, resolve, reject } = this.queue.shift();
  
		try {
		  const response = await request();
		  resolve(response);
		} catch (error) {
		  reject(error);
		} finally {
		  this.currentlyProcessing--;
		  await this.process();
		}
	  }
	}
  
	// Pause the queue processing
	pause() {
	  this.isPaused = true;
	}
  
	// Resume the queue processing
	resume() {
	  this.isPaused = false;
	  this.process(); // Continue processing when resumed
	}
  
	// Clear pending requests in the queue
	clear() {
	  this.queue.length = 0;
	}
  }