Add the include_tableofcontents traitlet and update the jinja templat…

…e accordingly.

nbconvert/exporters/templateexporter.py

@@ -203,6 +203,10 @@ def default_config(self):
     enable_async = Bool(False, help="Enable Jinja async template execution").tag(
         affects_environment=True
     )
+
+    include_tableofcontents = Bool(False, allow_none=True, help="Enable to include a table of contents").tag(
+       config=True, affects_template=True
+    )
 
     _last_template_file = ""
     _raw_template_key = "<memory>"
@@ -683,7 +687,4 @@ def _init_resources(self, resources):
         resources["include_tableofcontents"] = self.include_tableofcontents
         return resources
 
-    def include_tableofcontents(self):
-        return True
-
 

share/templates/lab/index.html.j2

@@ -177,6 +177,7 @@ a.anchor-link {
 {% endif %}
 <main>
 {%- block tableofcontents -%}
+{%- if resources.include_tableofcontents -%}
 <div class="jp-RenderedHTMLTOC-Title">Table of contents</div>
 {%- for item in resources.tableofcontents -%}
 {%- set (level, text, id, href) = item -%}
@@ -223,6 +224,7 @@ a.anchor-link {
 </div>
 {%- endif -%}
 {%- endfor -%}
+{%- endif -%}
 {% endblock tableofcontents %}
 {%- endblock body_header -%}