From @lucaswoj on December 23, 2016 14:41

Working with Mapbox style spec objects in Javascript is less ergonomic because all the dashcase properties must be quoted when they are used as identifiers.

var layer = { 'line-color': 'blue' }
layer['line-color']

vs

var layer = { lineColor: 'blue' }
layer.lineColor

They look odd in conjunction with the camelcased source properties #175

Copied from original issue: mapbox/mapbox-gl-style-spec#638