Handle promise rejection for sound.play() in preload

[epicfaace]

The basics

• I branched from develop
• My pull request is against develop
• My code follows the style guide

The details

Resolves

audio play() called before user interaction #1902

Handle promise rejection for sound.play() in preload. This removes the error, "play() failed because the user didn't interact with the document first."

Test Coverage

Tested on:

• Desktop Chrome

Mac OS X

Additional Information

[RoboErikG]

Whoops, hit approve too quickly. Couple problems,

1. This uses an ES6 feature. Blockly is still written in ES5 for compatibility with older browsers.
2. This pull request is against master, it should be against develop.

[epicfaace]

@RoboErikG thanks, I've fixed those problems.

Why doesn't Blockly use Babel?

[AnmAtAnm]

@RoboErikG @rachel-fenichel
I think this is still a problem for older browsers. The return value of play() will be undefined in older browsers, and that needs to be tested before calling catch(..). Fixing this would probably make this a solid solution.
Unfortunately, this was pushed into the latest release.

@epicfaace I don't think Babel would fix this particular case.

[rachel-fenichel]

@AnmAtAnm so does this now fail differently for older browsers, and in a way that we need to be concerned about? Or is it just that this solution doesn't get rid of the warning in the older browsers?

[tuxianchao]

In my project, play-request-was-interrupted this is how I solved the problem.

[NeilFraser]

Any changes to sound need to be tested on all browsers (including IE), iOS, and Android. Sound is a surprisingly immature and inconsistent beast. The current Rube Goldberg method in which Blockly plays sound is a result of playing whack-a-mole until a working solution emerged. Specs and logic are irrelevant, it's all driven by the random implementations of each browser.

[tuxianchao]

@RoboErikG @rachel-fenichel
I think this is still a problem for older browsers. The return value of play() will be undefined in older browsers, and that needs to be tested before calling catch(..). Fixing this would probably make this a solid solution.
Unfortunately, this was pushed into the latest release.

@epicfaace I don't think Babel would fix this particular case.

may be like this,check play() method return promise before pause()

var playPromise =  sound.play();
if(playPromise !== undefined){
     playPromise.then(function(){
         sound.pause();
     }).catch(function(error){
          console.error(error);
         //....
     });
}