feat: add imperative api to refresh state (#594)

* feat: add imperative api to refresh state
* docs: document refresh in README
* Add example to example app
* Update netinfo mock with refresh method

README.md

@@ -148,6 +148,7 @@ NetInfo.fetch().then(state => {
   * [`NetInfoCellularGeneration`](#netinfocellulargeneration)
 * **Methods:**
   * [`fetch()`](#fetch)
+  * [`refresh()`](#refresh)
   * [`addEventListener()`](#addeventlistener)
   * [`useNetInfo()`](#usenetinfo)
 
@@ -345,6 +346,20 @@ NetInfo.fetch("wifi").then(state => {
 });
 ```
 
+#### `refresh()`
+
+Updates NetInfo's internal state, then returns a `Promise` that resolves to a [`NetInfoState`](#netinfostate) object. This is similar to `fetch()`, but really only useful on platforms that do not supply internet reachability natively. For example, you can use it to immediately re-run an internet reachability test if a network request fails unexpectedly.
+
+**Example:**
+```javascript
+NetInfo.refresh().then(state => {
+    console.log("Connection type", state.type);
+    console.log("Is connected?", state.isConnected);
+});
+```
+
+This will also update subscribers using `addEventListener` and/or `useNetInfo`.
+
 ## Troubleshooting
 
 ### Errors when building on Android

example/ConnectionInfoRefresh.tsx

@@ -0,0 +1,46 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import * as React from 'react';
+import {Text, View, TouchableOpacity} from 'react-native';
+import NetInfo from '../src';
+
+interface State {
+  connectionInfo: string;
+}
+
+export default class ConnectionInfoCurrent extends React.Component<
+  Record<string, unknown>,
+  State
+> {
+  state = {
+    connectionInfo: 'Tap to refresh state',
+  };
+
+  componentDidMount(): void {
+    this._refreshState();
+  }
+
+  _refreshState = async (): Promise<void> => {
+    const state = await NetInfo.refresh();
+    this.setState({
+      connectionInfo: JSON.stringify(state),
+    });
+  };
+
+  render() {
+    return (
+      <View>
+        <TouchableOpacity onPress={this._refreshState}>
+          <Text style={{color: 'black'}}>{this.state.connectionInfo}</Text>
+        </TouchableOpacity>
+      </View>
+    );
+  }
+}

example/index.tsx

@@ -23,6 +23,7 @@ import {
 import ConnectionInfoSubscription from './ConnectionInfoSubscription';
 import ConnectionInfoCurrent from './ConnectionInfoCurrent';
 import ConnectionInfoFetch from './ConnectionInfoFetch';
+import ConnectionInfoRefresh from './ConnectionInfoRefresh';
 import NetInfoHook from './NetInfoHook';
 import IsConnected from './IsConnected';
 
@@ -51,6 +52,14 @@ const EXAMPLES: Example[] = [
       return <ConnectionInfoFetch />;
     },
   },
+  {
+    id: 'refresh',
+    title: 'NetInfo.refresh',
+    description: 'Refresh the state on tap',
+    render() {
+      return <ConnectionInfoRefresh />;
+    },
+  },
   {
     id: 'currentInfoSingle',
     title: 'Current Info Single',

jest/netinfo-mock.js

@@ -16,11 +16,13 @@ const defaultState = {
 const RNCNetInfoMock = {
   configure: jest.fn(),
   fetch: jest.fn(),
+  refresh: jest.fn(),
   addEventListener: jest.fn(),
   useNetInfo: jest.fn(),
 };
 
 RNCNetInfoMock.fetch.mockResolvedValue(defaultState);
+RNCNetInfoMock.refresh.mockResolvedValue(defaultState);
 RNCNetInfoMock.useNetInfo.mockReturnValue(defaultState);
 RNCNetInfoMock.addEventListener.mockReturnValue(jest.fn());
 

src/index.ts

@@ -64,6 +64,18 @@ export function fetch(
   return _state.latest(requestedInterface);
 }
 
+/**
+ * Force-refreshes the internal state of the NetInfo library.
+ *
+ * @returns A Promise which contains the updated connection state.
+ */
+export function refresh(): Promise<Types.NetInfoState> {
+  if (!_state) {
+    _state = createState();
+  }
+  return _state._fetchCurrentState();
+}
+
 /**
  * Subscribe to connection information. The callback is called with a parameter of type
  * [`NetInfoState`](README.md#netinfostate) whenever the connection state changes. Your listener
@@ -119,6 +131,7 @@ export * from './internal/types';
 export default {
   configure,
   fetch,
+  refresh,
   addEventListener,
   useNetInfo,
 };

src/internal/state.ts

@@ -65,7 +65,7 @@ export default class State {
     this._subscriptions.forEach((handler): void => handler(nextState));
   };
 
-  private _fetchCurrentState = async (
+  public _fetchCurrentState = async (
     requestedInterface?: string,
   ): Promise<Types.NetInfoState> => {
     const state = await NativeInterface.getCurrentState(requestedInterface);