Re: Slides from TV Control WG joint meeting

Hi,

And thanks Chris,
as I can not directly participate to those Working Group Meetings (not W3C
Member any more), it is good to still be able to follow.

I don't won't to look rude or like trolling or anything, but I think it is
important to make examples that better use promises, for which, one of the
announced purpose is to prevent issues like "callback hell".

it is not just a kind of dev preference, but I think it is also even more
important in presentations to better understand the presented execution
steps

Such code using promise based APIs (slide 5)

navigator.tv.getTuners().then(function(tuners) {
    var tuner = tuners[0];
    tuner.setCurrentSource("dvb-t2").then(function() {
        tuner.currentSource.setCurrentChannel("101").then(function() {
            videoElement.srcObject = tuner.stream;
        }
    }
});

Is (I think) better meant to be written (with a more readable process) at
least as (in ES5)

navigator.tv.getTuners().then(function(tuners) {
    var tuner = tuners[0];
    return tuner.setCurrentSource("dvb-t2");
}).then(function() {
    return tuner.currentSource.setCurrentChannel("101");
}).then(function() {
    videoElement.srcObject = tuner.stream;
});

Such code structure is also more similar to what ES6 users would have
written

navigator.tv.getTuners()
    .then(tuners => {
        var tuner = tuners[0];
        return tuner.setCurrentSource("dvb-t2");
    })
    .then(() => tuner.currentSource.setCurrentChannel("101"))
    .then(() => videoElement.srcObject = tuner.stream);

(Just for fun) As to what ES8 users start to be able to write

async function play() {
    var tuners = async navigator.tv.getTuners();
    var tuner = tuners[0];
    await tuner.setCurrentSource("dvb-t2");
    await tuner.currentSource.setCurrentChannel("101");
    videoElement.srcObject = tuner.stream;
}

I don't care to see any of the 3 (ES5 / ES6 / ES8) mentioned variants, as,
even if the last one is probably the most "right to the point" version,
some may not be yet very comfortable with the more recent Arrow or
async functions.

But I think it could be a good thing to at least prevent from using code
structures as the one in slides 5 and 6

Regards,

Alexandre


2016-09-19 17:17 GMT+02:00 Chris Needham <chris.needham@bbc.co.uk>:

> Hi all,
>
> Please find attached the slides from the Web and TV IG / TV Control WG
> joint meeting this morning.
>
> Best regards,
>
> Chris (TV Control WG Chair)
>
>
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