queue.js

class RequestQueue {
	queue: Promise<void> = Promise.resolve();

	constructor() {
		const $this = this;
	}

	async add(fn: any) {
		const $this = this;

		$this.queue = $this.queue.then(fn, fn);

		return $this.queue;
	}
}

const queue = new RequestQueue();

queue.add(async () => await fetch('https://google.com/1'));
queue.add(async () => await fetch('https://google.com/2'));
queue.add(async () => await fetch('https://google.com/3'));
const response: any = await queue.add(async () => await fetch('https://google.com/4'));