Add ExternalWrapper to dash_component_api

@plotly/dash-test-components/src/components/ExternalComponent.js

@@ -0,0 +1,28 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+
+const ExternalComponent = ({ id, text, input_id }) => {
+    const ctx = window.dash_component_api.useDashContext();
+    const ExternalWrapper = window.dash_component_api.ExternalWrapper;
+
+    return (
+        <div id={id}>
+            <ExternalWrapper
+                id={input_id}
+                componentType="Input"
+                componentNamespace="dash_core_components"
+                value={text}
+                componentPath={[...ctx.componentPath, 'external']}
+            />
+        </div>
+    )
+}
+
+ExternalComponent.propTypes = {
+    id: PropTypes.string,
+    text: PropTypes.string,
+    input_id: PropTypes.string,
+};
+
+export default ExternalComponent;

@plotly/dash-test-components/src/index.js

@@ -13,6 +13,7 @@ import AddPropsComponent from "./components/AddPropsComponent";
 import ReceivePropsComponent from "./components/ReceivePropsComponent";
 import ShapeOrExactKeepOrderComponent from "./components/ShapeOrExactKeepOrderComponent";
 import ArrayOfExactOrShapeWithNodePropAssignNone from './components/ArrayOfExactOrShapeWithNodePropAssignNone';
+import ExternalComponent from './components/ExternalComponent';
 
 
 export {
@@ -29,5 +30,6 @@ export {
     AddPropsComponent,
     ReceivePropsComponent,
     ShapeOrExactKeepOrderComponent,
-    ArrayOfExactOrShapeWithNodePropAssignNone
+    ArrayOfExactOrShapeWithNodePropAssignNone,
+    ExternalComponent,
 };

dash/dash-renderer/src/actions/constants.js

@@ -8,7 +8,9 @@ const actionList = {
     SET_CONFIG: 1,
     ADD_HTTP_HEADERS: 1,
     ON_ERROR: 1,
-    SET_HOOKS: 1
+    SET_HOOKS: 1,
+    INSERT_COMPONENT: 1,
+    REMOVE_COMPONENT: 1
 };
 
 export const getAction = action => {

dash/dash-renderer/src/actions/index.js

@@ -18,6 +18,8 @@ export const setLayout = createAction(getAction('SET_LAYOUT'));
 export const setPaths = createAction(getAction('SET_PATHS'));
 export const setRequestQueue = createAction(getAction('SET_REQUEST_QUEUE'));
 export const updateProps = createAction(getAction('ON_PROP_CHANGE'));
+export const insertComponent = createAction(getAction('INSERT_COMPONENT'));
+export const removeComponent = createAction(getAction('REMOVE_COMPONENT'));
 
 export const dispatchError = dispatch => (message, lines) =>
     dispatch(

dash/dash-renderer/src/dashApi.ts

@@ -2,6 +2,7 @@ import {path} from 'ramda';
 import {DashContext, useDashContext} from './wrapper/DashContext';
 import {getPath} from './actions/paths';
 import {getStores} from './utils/stores';
+import ExternalWrapper from './wrapper/ExternalWrapper';
 
 /**
  * Get the dash props from a component path or id.
@@ -28,6 +29,7 @@ function getLayout(componentPathOrId: string[] | string): any {
 }
 
 (window as any).dash_component_api = {
+    ExternalWrapper,
     DashContext,
     useDashContext,
     getLayout

dash/dash-renderer/src/reducers/layout.js

@@ -1,4 +1,12 @@
-import {includes, mergeRight, append, view, lensPath, assocPath} from 'ramda';
+import {
+    includes,
+    mergeRight,
+    append,
+    view,
+    lensPath,
+    assocPath,
+    dissocPath
+} from 'ramda';
 
 import {getAction} from '../actions/constants';
 
@@ -20,6 +28,14 @@ const layout = (state = {}, action) => {
         const mergedProps = mergeRight(existingProps, action.payload.props);
         return assocPath(propPath, mergedProps, state);
     }
+    // Custom component rendered out of tree.
+    else if (action.type === getAction('INSERT_COMPONENT')) {
+        const {component, componentPath} = action.payload;
+        return assocPath(componentPath, component, state);
+    } else if (action.type === getAction('REMOVE_COMPONENT')) {
+        const {componentPath} = action.payload;
+        return dissocPath(componentPath, state);
+    }
 
     return state;
 };

dash/dash-renderer/src/wrapper/DashContext.tsx

@@ -9,15 +9,19 @@ type LoadingFilterFunc = (loading: LoadingPayload) => boolean;
 
 type LoadingOptions = {
     /**
-     *
+     * Path to add after the current component if loading.
+     * Ex `["props"]` will return true only for when that component load.
      */
     extraPath?: DashLayoutPath;
     /**
-     *
+     * A raw path used instead of the current component.
+     * Useful if you want the loading of a child component
+     * as the path is available in `child.props.componentPath`.
      */
     rawPath?: boolean;
     /**
      * Function used to filter the properties of the loading component.
+     * Filter argument is an Entry of `{path, property, id}`.
      */
     filterFunc?: LoadingFilterFunc;
 };
@@ -113,5 +117,12 @@ export function DashContextProvider(props: DashContextProviderProps) {
 }
 
 export function useDashContext() {
-    return useContext(DashContext);
+    const ctx = useContext(DashContext);
+    if (!ctx) {
+        // eslint-disable-next-line no-console
+        console.error(
+            'Dash Context was not found, component was rendered without a wrapper. Use `window.dash_component_api.ExternalWrapper` to make sure the component is properly connected.'
+        );
+    }
+    return ctx || {};
 }

dash/dash-renderer/src/wrapper/DashWrapper.tsx

@@ -422,10 +422,24 @@ function DashWrapper({
     );
 }
 
-export default memo(
-    DashWrapper,
-    (prevProps, nextProps) =>
-        JSON.stringify(prevProps.componentPath) ===
-            JSON.stringify(nextProps.componentPath) &&
-        prevProps._dashprivate_error === nextProps._dashprivate_error
-);
+function wrapperEquality(prev: any, next: any) {
+    const {
+        componentPath: prevPath,
+        _dashprivate_error: prevError,
+        ...prevProps
+    } = prev;
+    const {
+        componentPath: nextPath,
+        _dashprivate_error: nextError,
+        ...nextProps
+    } = next;
+    if (JSON.stringify(prevPath) !== JSON.stringify(nextPath)) {
+        return false;
+    }
+    if (prevError !== nextError) {
+        return false;
+    }
+    return equals(prevProps, nextProps);
+}
+
+export default memo(DashWrapper, wrapperEquality);

dash/dash-renderer/src/wrapper/ExternalWrapper.tsx

@@ -0,0 +1,52 @@
+import React, {useState, useEffect} from 'react';
+import {useDispatch} from 'react-redux';
+
+import {DashLayoutPath} from '../types/component';
+import DashWrapper from './DashWrapper';
+import {insertComponent, removeComponent} from '../actions';
+
+type Props = {
+    componentPath: DashLayoutPath;
+    componentType: string;
+    componentNamespace: string;
+    [k: string]: any;
+};
+
+/**
+ * For rendering components that are out of the regular layout tree.
+ */
+function ExternalWrapper({
+    componentType,
+    componentNamespace,
+    componentPath,
+    ...props
+}: Props) {
+    const dispatch = useDispatch();
+    const [inserted, setInserted] = useState(false);
+
+    useEffect(() => {
+        // Give empty props for the inserted components.
+        // The props will come from the parent so they can be updated.
+        dispatch(
+            insertComponent({
+                component: {
+                    type: componentType,
+                    namespace: componentNamespace,
+                    props: {}
+                },
+                componentPath
+            })
+        );
+        setInserted(true);
+        return () => {
+            dispatch(removeComponent({componentPath}));
+        };
+    }, []);
+
+    if (!inserted) {
+        return null;
+    }
+    // Render a wrapper with the actual props.
+    return <DashWrapper componentPath={componentPath} {...props} />;
+}
+export default ExternalWrapper;

tests/integration/renderer/test_external_component.py

@@ -0,0 +1,27 @@
+from dash import Dash, html, dcc, html, Input, Output, State
+from dash_test_components import ExternalComponent
+
+
+def test_rext001_render_external_component(dash_duo):
+    app = Dash()
+    app.layout = html.Div(
+        [
+            dcc.Input(id="sync", value="synced"),
+            html.Button("sync", id="sync-btn"),
+            ExternalComponent("ext", input_id="external", text="external"),
+        ]
+    )
+
+    @app.callback(
+        Output("ext", "text"),
+        Input("sync-btn", "n_clicks"),
+        State("sync", "value"),
+        prevent_initial_call=True,
+    )
+    def on_sync(_, value):
+        return value
+
+    dash_duo.start_server(app)
+    dash_duo.wait_for_text_to_equal("#external", "external")
+    dash_duo.find_element("#sync-btn").click()
+    dash_duo.wait_for_text_to_equal("#external", "synced")