[ExpansionPanel] Add context

Author: eps1lon

packages/material-ui/src/ExpansionPanel/ExpansionPanelContext.js

@@ -0,0 +1,18 @@
+import React from 'react';
+import warning from 'warning';
+
+const ExpansionPanelContext = React.createContext({
+  disabled: false,
+  expanded: false,
+  onChange: () => {
+    warning(
+      false,
+      [
+        'Material-UI: You called onChange from a component  that is not a child of a ',
+        'ExpansionPanel component.',
+      ].join(''),
+    );
+  },
+});
+
+export default ExpansionPanelContext;

packages/material-ui/src/ExpansionPanel/index.js

@@ -1 +1,2 @@
 export { default } from './ExpansionPanel';
+export { default as useExpansionPanel } from './useExpansionPanel';

packages/material-ui/src/ExpansionPanel/useExpansionPanel.d.ts

@@ -0,0 +1,11 @@
+import * as React from 'react';
+
+interface ExpansionPanelContext<ChangeEvent> {
+  disabled: boolean;
+  expanded: boolean;
+  onChange: (event: Event, expanded: boolean) => void;
+}
+
+export default function useExpansionPanel<
+  ChangeEvent = React.SyntheticEvent
+>(): ExpansionPanelContext<ChangeEvent>;

packages/material-ui/src/ExpansionPanel/useExpansionPanel.js

@@ -0,0 +1,6 @@
+import React from 'react';
+import ExpansionPanelContext from './ExpansionPanelContext';
+
+export default function useExpansionPanel() {
+  return React.useContext(ExpansionPanelContext);
+}