Markdown issue with airbnb/javascript

Im currently trying to import the airbnb javascript guideline. The README Markdown does not get rendered properly however. At some parts (quite a lot actually) I see the markdown ‘code’ (e.g.this) instead of the rendered javascript code.
Does anyone know why this happen or how I can fix it? I tried changing the indentation but that would mean that I would have to change it on every code snippet.
The strange thing is that some are working and some are not.