The MediaTrackSettings dictionary's noiseSuppression property is a Boolean value whose value indicates whether or not noise suppression technology is enabled on an audio track. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the MediaTrackConstraints.noiseSuppression property you provided when calling either getUserMedia() or MediaStreamTrack.applyConstraints().
Noise suppression automatically filters the audio to remove background noise, hum caused by equipment, and the like from the sound before delivering it to your code. This feature is typically used on microphones, although it is technically possible it could be provided by other input sources as well.
If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.noiseSuppression as returned by a call to MediaDevices.getSupportedConstraints(). However, typically this is unnecessary since browsers will ignore any constraints they're unfamiliar with.
