Recently, I got the following tip how to convert a json file to VL spec. It allows to manipulate vl spec easily using a dictionary and convert it to a plot. I think it might be useful to many VegaLite.jl users. How about adding the tip in the document?
using VegaLite: VLSpec
using JSON
using DataStructures: OrderedDict
p = VLSpec(JSON.parse(open("vegalite.json", dicttype=OrderedDict)))
(Used ```OrderedDict`` to preserve the order of items)