Delay get plotlyjs version

Author: T4rk1n

Diff for: components/dash-core-components/dash_core_components_base/__init__.py

@@ -2,8 +2,6 @@
 import os as _os
 import sys as _sys
 
-from plotly.offline import get_plotlyjs_version
-
 import dash as _dash
 
 from ._imports_ import *  # noqa: F401, F403, E402
@@ -124,12 +122,6 @@
             "namespace": "dash",
             "dynamic": True,
         },
-        {
-            "relative_package_path": "package_data/plotly.min.js",
-            "external_url": f"https://cdn.plot.ly/plotly-{get_plotlyjs_version()}.min.js",
-            "namespace": "plotly",
-            "async": "eager",
-        },
         {
             "relative_package_path": "dcc/async-plotlyjs.js",
             "external_url": (

Diff for: dash/dash.py

@@ -20,7 +20,6 @@
 import flask
 
 from pkg_resources import get_distribution, parse_version
-from plotly.offline import get_plotlyjs_version
 
 from dash import dcc
 from dash import html
@@ -342,6 +341,8 @@ class Dash:
         if not added previously.
     """
 
+    _plotlyjs_url: str
+
     def __init__(  # pylint: disable=too-many-statements
         self,
         name=None,
@@ -589,6 +590,8 @@ def _handle_error(_):
         _get_app.APP = self
         self.enable_pages()
 
+        self._setup_plotlyjs()
+
     def _add_url(self, name, view_func, methods=("GET",)):
         full_name = self.config.routes_pathname_prefix + name
 
@@ -620,6 +623,25 @@ def _setup_routes(self):
         # catch-all for front-end routes, used by dcc.Location
         self._add_url("<path:path>", self.index)
 
+    def _setup_plotlyjs(self):
+        # pylint: disable=import-outside-toplevel
+        from plotly.offline import get_plotlyjs_version
+
+        url = f"https://cdn.plot.ly/plotly-{get_plotlyjs_version()}.min.js"
+
+        # pylint: disable=protected-access
+        dcc._js_dist.extend(
+            [
+                {
+                    "relative_package_path": "package_data/plotly.min.js",
+                    "external_url": url,
+                    "namespace": "plotly",
+                    "async": "eager",
+                }
+            ]
+        )
+        self._plotlyjs_url = url
+
     @property
     def layout(self):
         return self._layout
@@ -706,9 +728,7 @@ def _config(self):
             "serve_locally": self.config.serve_locally,
         }
         if not self.config.serve_locally:
-            config[
-                "plotlyjs_url"
-            ] = f"https://cdn.plot.ly/plotly-{get_plotlyjs_version()}.min.js"
+            config["plotlyjs_url"] = self._plotlyjs_url
         if self._dev_tools.hot_reload:
             config["hot_reload"] = {
                 # convert from seconds to msec as used by js `setInterval`