Updated json pane to accept single quote

panel/models/json.ts

@@ -15,7 +15,7 @@ export class JSONView extends PanelMarkupView {
 
   render(): void {
     super.render();
-    const text = this.model.text.replace(/(\r\n|\n|\r)/gm, "").replace("'", '"')
+    const text = this.model.text.replace(/(\r\n|\n|\r)/gm, "")
     let json;
     try {
       json = window.JSON.parse(text)

panel/pane/markup.py

@@ -338,10 +338,11 @@ def applies(cls, obj, **params):
 
     def _get_properties(self):
         properties = super()._get_properties()
-        if isinstance(self.object, string_types):
-            text = self.object
-        else:
-            text = json.dumps(self.object or {}, cls=self.encoder)
+        try:
+            data = json.loads(self.object)
+        except Exception:
+            data = self.object
+        text = json.dumps(data or {}, cls=self.encoder)
         depth = None if self.depth < 0 else self.depth
         return dict(text=text, theme=self.theme, depth=depth,
                     hover_preview=self.hover_preview, **properties)

panel/tests/pane/test_markup.py

@@ -205,6 +205,22 @@ def test_json_pane(document, comm):
     assert model.text == '{"b": 3}'
     assert pane._models[model.ref['id']][0] is model
 
+    pane.object = {"test": "can't show this"}
+    assert model.text == '{"test": "can\'t show this"}'
+    assert pane._models[model.ref['id']][0] is model
+
+    pane.object = ["can't show this"]
+    assert model.text == '["can\'t show this"]'
+    assert pane._models[model.ref['id']][0] is model
+
+    pane.object = "can't show this"
+    assert model.text == '"can\'t show this"'
+    assert pane._models[model.ref['id']][0] is model
+
+    pane.object = "can show this"
+    assert model.text == '"can show this"'
+    assert pane._models[model.ref['id']][0] is model
+
     # Cleanup
     pane._cleanup(model)
     assert pane._models == {}