python Bokeh: DataTable cells styling - bokeh

Question

I'd like to have a custom formatter for one my dataTable cells.
Say, for example I'd like to have the title column font style in bold.
from bokeh.plotting import show
from bokeh.models.sources import ColumnDataSource
from bokeh.models.widgets import DataTable, TableColumn
if __name__ == '__main__':
source = ColumnDataSource(data = dict(hello = ["one", "two", "three"]))
c0 = TableColumn(field="hello",
title= "TITLE IN BOLD?")
ds = DataTable(source=source,
columns = [c0])
show(ds)
Is there a simple way to do this in BokehJS?
Thanks

Answer 1

Using the HTMLTemplateFormatter can get the job done. This allows all cells in the column to be formatted as code so you can add in bold tags or what ever else you want in any of the cells.
Note: if you are using bokeh version 0.12.5 Unfortunately they have removed underscore js so to get around it (first block of ugly code), you can use the work around from this github issue: https://github.com/bokeh/bokeh/issues/6207. Or alternatively include underscorejs/lodash in the output html file, i.e. <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/lodash.js/0.10.0/lodash.min.js"></script>
from bokeh.models.widgets import HTMLTemplateFormatter
from bokeh.plotting import show
from bokeh.models.sources import ColumnDataSource
from bokeh.models.widgets import DataTable, TableColumn
class MyHTMLFormatter(HTMLTemplateFormatter):
__javascript__ = ["https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"]
__implementation__ = """
import {HTMLTemplateFormatter} from "models/widgets/cell_formatters"
export class MyHTMLFormatter extends HTMLTemplateFormatter
type: 'MyHTMLFormatter'
"""
if __name__ == '__main__':
source = ColumnDataSource(data = dict(hello = ["<b>one</b>", "two", "three"]))
formatter = HTMLTemplateFormatter(template='<code><%= value %></code>')
c0 = TableColumn(field="hello",
title= "<b>TITLE IN BOLD?</b>", formatter=formatter)
ds = DataTable(source=source,
columns = [c0])
show(ds)