Remove method-chaining capabilities for player.currentTime

[dmlap]

Method chaining can save some repetitious typing when using the player APIs:

player.currentTime(7).play();

Unfortunately, switching return types between different function invocations confuses Javascript optimizers and often means the method remains de-optimized. For methods that may be called very frequently during player interactions like currentTime, de-optimized functions that take 10s of milliseconds can lead to frame drops.

[dmlap]

Here's a sample timeline profile from Chrome. Note in the bottom pane thatcurrentTime is de-optimized and took over 10ms of self-time:

[misteroneill]

I think we all agree that we should either do nothing or remove all method-chaining capabilities from video.js.

Presuming we remove method-chaining capabilities, one thing we need to discuss is what to do about returning a Promise from play() (which Chrome does) instead of this. There are a few options:

1. Return whatever the browser (and the tech) return.
2. Return a promise if the browser returns one. If the browser does not return a promise, but the browser supports promises, return our own pre-resolved promise. Otherwise, return nothing/undefined.
3. Always return a promise. This would require users to use a promise-providing library like es6-shim or Bluebird for browsers that don't support promises.

[brandonocasey]

I really like solution 2, but maybe we could make it check if Promises are available instead of depending on a browser check. That way if the promise-providing library provides a Promise or a native Promise exists we can use it, but it won't force anyone to use a promise library.

[misteroneill]

Yep, agreed.

[dmlap]

Solution 2 sounds right to me, too.

[misteroneill]

Sounds pretty uncontroversial, then.