Inspect non-utf8 binaries (#112)

lib/kino/explorer.ex

@@ -124,7 +124,18 @@ defmodule Kino.Explorer do
   end
 
   defp records_to_data(columns, records) do
-    Enum.map(columns, fn column -> Map.fetch!(records, column.key) |> Enum.map(&to_string/1) end)
+    Enum.map(columns, fn column ->
+      records |> Map.fetch!(column.key) |> Enum.map(&value_to_string(column.type, &1))
+    end)
+  end
+
+  defp value_to_string("binary", value) do
+    inspect_opts = Inspect.Opts.new([])
+    if String.printable?(value, inspect_opts.limit), do: value, else: inspect(value)
+  end
+
+  defp value_to_string(_type, value) do
+    to_string(value)
   end
 
   defp summaries(df, groups) do
@@ -194,6 +205,7 @@ defmodule Kino.Explorer do
 
   defp type_of(:boolean, _), do: "boolean"
   defp type_of(:string, [data]), do: type_of_sample(data)
+  defp type_of(:binary, _), do: "binary"
   defp type_of(_, _), do: "text"
 
   defp type_of_sample("http" <> _rest), do: "uri"

test/kino/explorer_test.exs

@@ -289,6 +289,21 @@ defmodule Kino.ExplorerTest do
            } = data
   end
 
+  test "correctly data frames with binary non-utf8 column values" do
+    df =
+      Explorer.DataFrame.new([x: [1, 2], y: [<<110, 120>>, <<200, 210>>]], dtypes: [y: :binary])
+
+    widget = Kino.Explorer.new(df)
+    data = connect(widget)
+
+    assert %{
+             features: [:export, :pagination, :sorting],
+             content: %{
+               data: [["1", "2"], ["nx", "<<200, 210>>"]]
+             }
+           } = data
+  end
+
   test "supports lazy data frames" do
     df = Explorer.Datasets.iris() |> Explorer.DataFrame.lazy()
     widget = Kino.Explorer.new(df)