Changes type checks to use a Protocol for JsCode

and JsCode like objects that come from external sources.

Author: hansthen

folium/elements.py

@@ -9,7 +9,7 @@
 )
 
 from folium.template import Template
-from folium.utilities import JsCode
+from folium.utilities import TypeJsCode
 
 
 class JSCSSMixin(MacroElement):
@@ -121,7 +121,7 @@ class EventHandler(MacroElement):
         """
     )
 
-    def __init__(self, event: str, handler: JsCode, once: bool = False):
+    def __init__(self, event: str, handler: TypeJsCode, once: bool = False):
         super().__init__()
         self._name = "EventHandler"
         self.event = event

folium/plugins/timeline.py

@@ -6,7 +6,7 @@
 from folium.features import GeoJson
 from folium.folium import Map
 from folium.template import Template
-from folium.utilities import JsCode, get_bounds, remove_empty
+from folium.utilities import JsCode, TypeJsCode, get_bounds, remove_empty
 
 
 class Timeline(GeoJson):
@@ -108,7 +108,7 @@ class Timeline(GeoJson):
     def __init__(
         self,
         data: Union[dict, str, TextIO],
-        get_interval: Optional[JsCode] = None,
+        get_interval: Optional[TypeJsCode] = None,
         **kwargs
     ):
         super().__init__(data)

folium/template.py

@@ -4,11 +4,11 @@
 import jinja2
 from branca.element import Element
 
-from folium.utilities import JsCode, TypeJsonValue, camelize
+from folium.utilities import TypeJsCode, TypeJsonValue, camelize
 
 
-def tojavascript(obj: Union[str, JsCode, dict, list, Element]) -> str:
-    if isinstance(obj, JsCode):
+def tojavascript(obj: Union[str, TypeJsCode, dict, list, Element]) -> str:
+    if isinstance(obj, TypeJsCode):
         return obj.js_code
     elif isinstance(obj, Element):
         return obj.get_name()

folium/utilities.py

@@ -17,10 +17,12 @@
     Iterator,
     List,
     Optional,
+    Protocol,
     Sequence,
     Tuple,
     Type,
     Union,
+    runtime_checkable,
 )
 from urllib.parse import urlparse, uses_netloc, uses_params, uses_relative
 
@@ -35,7 +37,6 @@
     none_min,
     write_png,
 )
-from js_loader import JsCode  # noqa: F401
 
 try:
     import pandas as pd
@@ -65,6 +66,25 @@
 _VALID_URLS.add("data")
 
 
+@runtime_checkable
+class TypeJsCode(Protocol):
+    # we only care about this attribute.
+    js_code: str
+
+
+class JsCode(TypeJsCode):
+    """Wrapper around Javascript code."""
+
+    def __init__(self, js_code: Union[str, "JsCode"]):
+        if isinstance(js_code, JsCode):
+            self.js_code: str = js_code.js_code
+        else:
+            self.js_code = js_code
+
+    def __str__(self):
+        return self.js_code
+
+
 def validate_location(location: Sequence[float]) -> List[float]:
     """Validate a single lat/lon coordinate pair and convert to a list
 

tests/test_utilities.py

@@ -1,10 +1,12 @@
 import numpy as np
 import pandas as pd
 import pytest
+from js_loader import JsCode as external_JsCode
 
 from folium import FeatureGroup, Map, Marker, Popup
 from folium.utilities import (
     JsCode,
+    TypeJsCode,
     _is_url,
     camelize,
     deep_copy,
@@ -248,6 +250,11 @@ def test_js_code_init_js_code():
     assert isinstance(js_code_2.js_code, str)
 
 
+def test_external_js_code():
+    js_code = external_JsCode("hi")
+    assert isinstance(js_code, TypeJsCode)
+
+
 @pytest.mark.parametrize(
     "value,expected",
     [