'The absolute path of the BokehJS source code in the installed
Bokeh source tree.'

def bokehjssrcdir(self):

    if (self._is_dev or self.debugjs):
        bokehjssrcdir = abspath(join(ROOT_DIR, '..', 'bokehjs', 'src'))
        if isdir(bokehjssrcdir):
            return bokehjssrcdir
    return None
