feat: make to_html deterministic

CHANGELOG.md

@@ -2,6 +2,7 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+
 ## UNRELEASED
 
 ### Fixed
@@ -11,7 +12,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
   - `text_auto` argument to `px.bar`, `px.histogram`, `px.density_heatmap`, `px.imshow` [#3518](https://github.com/plotly/plotly.py/issues/3518)
   - Deprecated `ff.create_annotated_heatmap`, `ff.create_county_choropleth`, `ff.create_gantt` [#3518](https://github.com/plotly/plotly.py/issues/3518)
-
+  - `div_id` argument to `pio.to_html` to optionally make its IDs deterministic [#3487](https://github.com/plotly/plotly.py/issues/3487)
+
 ### Updated
   - Updated Plotly.js to from version 2.6.3 to version 2.8.1. See the [plotly.js CHANGELOG](https://github.com/plotly/plotly.js/blob/master/CHANGELOG.md#280----2021-12-10) for more information. Notable changes include:
     - Horizontal color bars

packages/python/plotly/plotly/io/_html.py

@@ -38,6 +38,7 @@ def to_html(
     default_width="100%",
     default_height="100%",
     validate=True,
+    div_id=None,
 ):
     """
     Convert a figure to an HTML string representation.
@@ -135,7 +136,7 @@ def to_html(
     fig_dict = validate_coerce_fig_to_dict(fig, validate)
 
     # ## Generate div id ##
-    plotdivid = str(uuid.uuid4())
+    plotdivid = div_id or str(uuid.uuid4())
 
     # ## Serialize figure ##
     jdata = to_json_plotly(fig_dict.get("data", []))
@@ -391,6 +392,7 @@ def write_html(
     default_width="100%",
     default_height="100%",
     auto_open=False,
+    div_id=None,
 ):
     """
     Write a figure to an HTML file representation
@@ -512,6 +514,7 @@ def write_html(
         default_width=default_width,
         default_height=default_height,
         validate=validate,
+        div_id=div_id,
     )
 
     # Check if file is a string

packages/python/plotly/plotly/tests/test_io/test_html.py

@@ -38,3 +38,10 @@ def fig1(request):
 
 def test_versioned_cdn_included(fig1):
     assert plotly_cdn_url() in pio.to_html(fig1, include_plotlyjs="cdn")
+
+
+def test_html_deterministic(fig1):
+    div_id = "plotly-root"
+    assert pio.to_html(fig1, include_plotlyjs="cdn", div_id=div_id) == pio.to_html(
+        fig1, include_plotlyjs="cdn", div_id=div_id
+    )