add alternates feature
how about adding alternates feature such as Stylistics Alternates and Contextual alternates?
This is a great idea. Unfortunately, at the moment we are restricted by the features supported in OpenType.js, and this is one of the OpenType features that is not currently supported by OpenType.js.
It is possible to include alternates in the Unicode "Private Use Area" which is the range 0xE000 to 0xF8FF - they will be part of the font, but they won't behave like OpenType contextual alternates.