ensure JSONText is never base64-encoded (#1081)

Author: stevengj

src/display.jl

@@ -87,7 +87,7 @@ function display_mimejson(mime_array::Vector{MIME}, x)
     error("No displayable MIME types in mime array.")
 end
 
-display_mimejson(m::MIME, x) = (m, JSON.JSONText(limitstringmime(m, x)))
+display_mimejson(m::MIME, x) = (m, JSON.JSONText(limitstringmime(m, x, true)))
 
 """
 Generate a dictionary of `mime_type => data` pairs for all registered MIME

src/inline.jl

@@ -34,9 +34,9 @@ InlineIOContext(io, KVs::Pair...) = IOContext(
 
 # convert x to a string of type mime, making sure to use an
 # IOContext that tells the underlying show function to limit output
-function limitstringmime(mime::MIME, x)
+function limitstringmime(mime::MIME, x, forcetext=false)
     buf = IOBuffer()
-    if istextmime(mime)
+    if forcetext || istextmime(mime)
         if israwtext(mime, x)
             return String(x)
         else