hack to display altair plots

Author: Christopher Doris

src/compat/multimedia.jl

@@ -34,7 +34,16 @@ function pyshow_rule_mimebundle(io::IO, mime::String, x::Py)
         else
             data = ans[mime]
         end
-        write(io, pyconvert(Union{String,Vector{UInt8}}, data))
+        data = pyconvert(Union{String,Vector{UInt8}}, data)
+        if mime == "text/html"
+            data = String(data)
+            if occursin("altair-viz-", data) && occursin("document.currentScript.previousElementSibling", data)
+                # unsatisfactory hack to get altair plots to display properly in pluto
+                # TODO: fix this upstream (in altair or pluto??)
+                data = replace(data, "document.currentScript.previousElementSibling" => "((document.currentScript || {}).previousElementSibling || {})")
+            end
+        end
+        write(io, data)
         return true
     catch exc
         if exc isa PyException