collapsible JSON objects for Jupyter notebooks

renderjson.py

class rjson(object):
    """
    (with modifications) from:
    https://www.reddit.com/r/IPython/comments/34t4m7/lpt_print_json_in_collapsible_format_in_ipython/
    which in turn is leveraging http://caldwell.github.io/renderjson/
    """
    def __init__(self, json_data, open='🔽', close='🔺', level=1):
        if isinstance(json_data, dict):
            self.json_str = json.dumps(json_data)
        else:
            self.json_str = json
        self.open = open
        self.close = close
        self.level = level
        self.uuid = str(uuid.uuid4())
        
    def _ipython_display_(self):
        display_html('<div id="{}" style="width:100%;"></div>'.format(self.uuid),
            raw=True
        )
        display_javascript("""
        require(["https://rawgit.com/caldwell/renderjson/master/renderjson.js"], function() {
          /* https://getemoji.com/ */
          renderjson.set_icons('%s', '%s')
                    .set_show_to_level(%d);
          document.getElementById('%s').appendChild(renderjson(%s))
        });
        """ % (self.open, self.close, self.level, self.uuid, self.json_str), raw=True)

this currently doesn't work with jupyter-lab, cf Calysto/calysto_processing#11