Set an Emoji as a custom Favicon in JupyterLab tabs

jl_favicon.py

# Set an Emoji as a custom Favicon in JupyterLab tabs
# Credits:
#  David Magnotti fir the idea using Jupyter Notebooks: https://twitter.com/davidmagnotti/status/1357757614625615872?s=20
#  Serge Droz for the javascript pluming

def set_fav_icon( s ):
    """Set the tab favicon to an emoji or a svg file"""
    from IPython.display import display, HTML
    import re
    
    if len(s) == 1:
        vb = '0 0 220 220'
        ih = '<text y=".9em" font-size="200">{}</text>'.format(s)
    else:
        vb = re.findall(r'viewBox\s*=[\s\'\"]+([\-\d\.\s]+)[\s\'\"]+', svg )[0]
        ih = re.findall(r'<svg[^<]+(<.+)</svg>', svg )[0]
    text = """<script>
      var id = document.activeElement.parentElement['id']
      var y = document.querySelectorAll('[data-id=' + id + ']')
      var x
      for (var i = 0; i < y.length; i++) {{
        x = y[i].children[0].children[0]
        x.setAttribute('viewBox','{}')
        x.innerHTML = '{}'
      }}
    </script>""".format(vb,ih)

    display(HTML(text))
    
set_fav_icon( '🐠' )