A small JavaScript package that uses the Audio Web API to convert microphone input to a frequency and corresponding musical note.
Intonate is a derivative of the npm package freelizer by sablevsky, which in turn implements an algorithm from cwilso's PitchDetect.
Intonate will add a few features that are needed for my upcoming project escalade, a scales trainer. If you are looking for a package to use in your own project, I would recommend using freelizer for now as it has some useful documentation. This package does not add many features in its current state, and is likely to change.