required children prop

@plotly/dash-generator-test-component-typescript/src/components/RequiredChildrenComponent.tsx

@@ -0,0 +1,12 @@
+import React from 'react';
+import { RequiredChildrenComponentProps } from "../props";
+
+
+const RequiredChildrenComponent = (props: RequiredChildrenComponentProps) => {
+  const {children} = props;
+  return <div>
+    {children}
+  </div>
+}
+
+export default RequiredChildrenComponent;

@plotly/dash-generator-test-component-typescript/src/index.ts

@@ -6,6 +6,7 @@ import WrappedHTML from './components/WrappedHTML';
 import FCComponent from './components/FCComponent';
 import EmptyComponent from './components/EmptyComponent';
 import MixedComponent from './components/MixedComponent';
+import RequiredChildrenComponent from './components/RequiredChildrenComponent';
 
 export {
   TypeScriptComponent,
@@ -16,4 +17,5 @@ export {
   FCComponent,
   EmptyComponent,
   MixedComponent,
+  RequiredChildrenComponent,
 };

@plotly/dash-generator-test-component-typescript/src/props.ts

@@ -48,3 +48,7 @@ export type WrappedHTMLProps = {
     children?: React.ReactNode;
     id?: string;
 } & Pick<React.ButtonHTMLAttributes<any>, 'autoFocus'>
+
+export type RequiredChildrenComponentProps = {
+  children: React.ReactNode;
+}

dash/development/_py_components_generation.py

@@ -1,7 +1,7 @@
 from collections import OrderedDict
 import copy
 import os
-from textwrap import fill
+from textwrap import fill, dedent
 
 from dash.development.base_component import _explicitize_args
 from dash.exceptions import NonExistentEventException
@@ -65,11 +65,8 @@ def __init__(self, {default_argtext}):
         _explicit_args = kwargs.pop('_explicit_args')
         _locals = locals()
         _locals.update(kwargs)  # For wildcard attrs and excess named props
-        args = {{k: _locals[k] for k in _explicit_args if k != 'children'}}
-        for k in {required_props}:
-            if k not in args:
-                raise TypeError(
-                    'Required argument `' + k + '` was not specified.')
+        args = {args}
+        {required_validation}
         super({typename}, self).__init__({argtext})
 '''
 
@@ -87,18 +84,40 @@ def __init__(self, {default_argtext}):
         description=description,
         prop_reorder_exceptions=prop_reorder_exceptions,
     ).replace("\r\n", "\n")
+    required_args = required_props(filtered_props)
+    is_children_required = 'children' in required_args
+    required_args = list(filter(lambda arg: arg != 'children', required_args))
 
     prohibit_events(props)
 
     # pylint: disable=unused-variable
     prop_keys = list(props.keys())
-    if "children" in props:
+    if "children" in props and "children" in list_of_valid_keys:
         prop_keys.remove("children")
         default_argtext = "children=None, "
+        args = "{k: _locals[k] for k in _explicit_args if k != 'children'}"
         argtext = "children=children, **args"
     else:
         default_argtext = ""
+        args = "{k: _locals[k] for k in _explicit_args}"
         argtext = "**args"
+
+    if len(required_args) == 0:
+        required_validation = ""
+    else:
+        required_validation = f"""
+        for k in {required_args}:
+            if k not in args:
+                raise TypeError(
+                    'Required argument `' + k + '` was not specified.')
+        """
+
+    if is_children_required:
+        required_validation += """
+        if 'children' not in _explicit_args:
+            raise TypeError('Required argument children was not specified.')
+        """
+
     default_arglist = [
         (
             f"{p:s}=Component.REQUIRED"
@@ -121,8 +140,8 @@ def __init__(self, {default_argtext}):
             )
 
     default_argtext += ", ".join(default_arglist + ["**kwargs"])
-    required_args = required_props(filtered_props)
     nodes = collect_nodes({k: v for k, v in props.items() if k != "children"})
+
     return c.format(
         typename=typename,
         namespace=namespace,
@@ -131,8 +150,9 @@ def __init__(self, {default_argtext}):
         list_of_valid_keys=list_of_valid_keys,
         docstring=docstring,
         default_argtext=default_argtext,
+        args=args,
         argtext=argtext,
-        required_props=required_args,
+        required_validation=required_validation,
         children_props=nodes,
         base_nodes=filter_base_nodes(nodes) + ["children"],
     )

dash/testing/application_runners.py

@@ -13,6 +13,7 @@
 import runpy
 import requests
 import psutil
+
 # pylint: disable=no-member
 import multiprocess
 
@@ -216,7 +217,7 @@ def __init__(self, keep_open=False, stop_timeout=3):
 
     # pylint: disable=arguments-differ
     def start(self, app, start_timeout=3, **kwargs):
-        self.port = kwargs.get('port', 8050)
+        self.port = kwargs.get("port", 8050)
 
         def target():
             app.scripts.config.serve_locally = True

tests/integration/devtools/test_hot_reload.py

@@ -88,7 +88,8 @@ def new_text(n):
 
     try:
         until(
-            lambda: dash_duo_mp.driver.execute_script("return window.cheese") == "gouda",
+            lambda: dash_duo_mp.driver.execute_script("return window.cheese")
+            == "gouda",
             timeout=10,
         )
     finally:
@@ -97,7 +98,8 @@ def new_text(n):
             f.write(old_hard)
 
     until(
-        lambda: dash_duo_mp.driver.execute_script("return window.cheese") == "roquefort",
+        lambda: dash_duo_mp.driver.execute_script("return window.cheese")
+        == "roquefort",
         timeout=10,
     )
 

tests/integration/renderer/test_component_as_prop.py

@@ -102,7 +102,7 @@ def test_rdcap001_component_as_prop(dash_duo):
                         "id": "multi2",
                         "first": Span("foo"),
                         "second": Span("bar"),
-                    }
+                    },
                 ],
             ),
         ]

tests/integration/test_generation.py

@@ -9,6 +9,7 @@
     TypeScriptComponent,
     TypeScriptClassComponent,
     StandardComponent,
+    RequiredChildrenComponent,
 )
 from dash_test_components import StyledComponent
 from dash.html import Button, Div
@@ -99,3 +100,10 @@ def test_gene003_max_props():
 
     with pytest.raises(TypeError):
         MyNestedComponent(valuey="nor this")
+
+
+def test_gene004_required_children_prop():
+    with pytest.raises(TypeError):
+        RequiredChildrenComponent()
+
+    RequiredChildrenComponent(children='worked')