Is it possible to integrate to mapbox-gl-leaflet?

[JeongJun-Lee]

I am using mapbox-gl-leaflet lib(https://github.com/mapbox/mapbox-gl-leaflet) on Angular App. How can I integrate this lib to the mapbox-gl-leaflet?
When I tried it, there is an error like this:

core.js:6189 ERROR Error: Uncaught (in promise): ReferenceError: mapboxgl is not defined
ReferenceError: mapboxgl is not defined
at openmaptiles-language.js:59