Detect Firefox support for screen sharing

Question

Firefox, since version 52, will support screen sharing via:

navigator.mediaDevices.getUserMedia({ video: { mediaSource: \'screen\' }}) 
  .then(stream =>          


        

Answer 1

a way to detect whether a browser supports { mediaSource: 'screen' }?

The pedantic answer is the following will tell you if the mediaSource constraint is supported:

console.log(!!navigator.mediaDevices.getSupportedConstraints().mediaSource);

Unfortunately, mediaSource is non-standard, and only implemented in Firefox. Firefox is as of this writing the only browser to enable screen-sharing without a plugin.

Chrome has a different non-standard API using chromeMediaSource available as a plug-in, using an older constraints syntax, but it (rightly) does not appear in the new getSupportedConstraints.

It's a bit of a mess still. Long-term browsers may end up implementing getDisplayMedia instead.