seriousManual/sync.html

## sync.html
<html>
    <head>
        <script>
            class Service {
                inProgress = null;

                async uploadData() {
                    if (!this.inProgress) {
                        console.log('ohay, I\'m actually doing a request');

                        this.inProgress = new Promise(resolve => {
                            // simulate a request by resolving after 3s
                            setTimeout(() => {
                                this.inProgress = null;
                                resolve(Math.random());
                            }, 3000);
                        });
                    }

                    return this.inProgress
                }
            }

            const service = new Service();

            (async function () {
                const results = await Promise.all([
                    service.uploadData(),
                    service.uploadData(),
                    service.uploadData(),
                    service.uploadData(),
                ]);
                console.log(results);

                console.log(await service.uploadData());
                console.log(await service.uploadData());
            })();
        </script>
    </head>
    <body>
        <h1>sync</h1>
    </body>
</html>
	<html>
	<head>
	<script>
	class Service {
	inProgress = null;

	async uploadData() {
	if (!this.inProgress) {
	console.log('ohay, I\'m actually doing a request');

	this.inProgress = new Promise(resolve => {
	// simulate a request by resolving after 3s
	setTimeout(() => {
	this.inProgress = null;
	resolve(Math.random());
	}, 3000);
	});
	}

	return this.inProgress
	}
	}

	const service = new Service();

	(async function () {
	const results = await Promise.all([
	service.uploadData(),
	service.uploadData(),
	service.uploadData(),
	service.uploadData(),
	]);
	console.log(results);

	console.log(await service.uploadData());
	console.log(await service.uploadData());
	})();
	</script>
	</head>
	<body>
	<h1>sync</h1>
	</body>
	</html>