Inactivity check contains incorrect variable declaration leading to flickering behavior

[pavelhoral]

Inactivity check is not behaving correctly as it "flickers" between states multiple times when the player is about to go to inactive state. The reason for this is incorrect variable declaration of inactivityTimeout variable in player.js#1923:

let activityCheck = this.setInterval(function() {
  let inactivityTimeout;
  // ...
  this.clearTimeout(inactivityTimeout);
  // ...
  inactivityTimeout = this.setTimeout(...)

Variable inactivityTimeout must be declared outside of the inner function to work properly (otherwise the clearTimeout is simply no-op).

[pavelhoral]

Demonstation of the incorrect behavior - http://jsbin.com/jipemubuhu/edit?js,output . Every inactivity timeout logs timeout occured in the browser console.

What to do: play video and move mouse in circles for 5 seconds
Expected output: see timeout occured once at the end of mouse movement
Observed incorrect output: timeout occured appears during the interaction and also after it ends

[heff]

Ah! Thanks for figuring this out. It was proving difficult to debug. Looks like we missed this requirement in the move to let scoping.