Introduce context provider in view component

docs/source/blocks/index.md

@@ -19,5 +19,6 @@ editcomponent
 block-style-wrapper
 extensions
 ssr
+viewcontext
 core/index
 ```

docs/source/blocks/viewcontext.md

@@ -0,0 +1,38 @@
+---
+myst:
+  html_meta:
+    "description": "Sharing a context between blocks"
+    "property=og:description": "Sharing a context between blocks"
+    "property=og:title": "context of view"
+    "keywords": "Volto, React, blocks, view, context"
+---
+
+(viewcontext-label)=
+
+# context of `View`
+
+```{versionadded} Volto 18.0.0-alpha.48
+```
+
+Sharing a context between blocks.
+
+Volto provides a context of the `View` component for the case that blocks need to know about each other.
+
+Example: tooltips generated from a glossary show up only on the first occurrence on a page.
+
+Initialize the context for your add-on:
+
+```js
+config.views.viewContext["volto-slate-glossary"] = [];
+```
+
+Get the context and use it:
+
+```js
+import { useViewContext } from '@plone/volto/components/theme/View/View';
+
+
+    let matchedGlossaryTerms = useViewContext("volto-slate-glossary");
+```
+
+

packages/volto/news/6394.feature

@@ -0,0 +1 @@
+Introduce context provider in view component. @ksuess

packages/volto/src/components/theme/View/View.jsx

@@ -11,6 +11,7 @@ import { Redirect } from 'react-router-dom';
 import { createPortal } from 'react-dom';
 import { injectIntl } from 'react-intl';
 import qs from 'query-string';
+import { cloneDeep } from 'lodash';
 
 import {
   ContentMetadataTags,
@@ -29,6 +30,8 @@ import {
 import config from '@plone/volto/registry';
 import SlotRenderer from '../SlotRenderer/SlotRenderer';
 
+const ViewContext = React.createContext();
+
 /**
  * View container class.
  * @class View
@@ -247,13 +250,15 @@ class View extends Component {
           }
         />
         <SlotRenderer name="aboveContent" content={this.props.content} />
-        <RenderedView
-          key={this.props.content['@id']}
-          content={this.props.content}
-          location={this.props.location}
-          token={this.props.token}
-          history={this.props.history}
-        />
+        <ViewContext.Provider value={cloneDeep(config.views.viewContext)}>
+          <RenderedView
+            key={this.props.content['@id']}
+            content={this.props.content}
+            location={this.props.location}
+            token={this.props.token}
+            history={this.props.history}
+          />
+        </ViewContext.Provider>
         <SlotRenderer name="belowContent" content={this.props.content} />
         {this.props.content.allow_discussion && (
           <Comments pathname={this.props.pathname} />
@@ -268,6 +273,16 @@ class View extends Component {
   }
 }
 
+export function useViewContext(name) {
+  const viewContext = React.useContext(ViewContext);
+
+  if (!viewContext) {
+    throw new Error('Using useViewContext hook outside of <View>');
+  }
+
+  return viewContext[name] || {};
+}
+
 export default compose(
   injectIntl,
   connect(

packages/volto/src/config/Views.jsx

@@ -138,3 +138,5 @@ export const layoutViewsNamesMapping = {
   view: 'Default view',
   default: 'Default view',
 };
+
+export const viewContext = {};

packages/volto/src/config/index.js

@@ -6,6 +6,7 @@ import {
   defaultView,
   errorViews,
   layoutViewsNamesMapping,
+  viewContext,
 } from './Views';
 import { nonContentRoutes } from './NonContentRoutes';
 import { nonContentRoutesPublic } from './NonContentRoutesPublic';
@@ -205,6 +206,7 @@ let config = {
     defaultView,
     errorViews,
     layoutViewsNamesMapping,
+    viewContext,
   },
   blocks: {
     requiredBlocks,