cleanup and open source JS BugReporting module

Summary:This is just the JS part of a bug reporting module that can be used with a pure JS flow or a native reporting
flow. It's handy for grabbing data from a bunch of random components, like the ids of the rows that are visible in a
list view at the time the bug is reported, or a description of the current navigation stack.

It's initialized in `AppRegistry` so it's always ready to go and bug reports will always include the universal
`runApplication` info, but won't actually do anything by default unless `collectExtraData` is called.

Note: some apps may call `runApplication` multiple times if they have multiple react native root views. This will just
overwrite the source so it will just report the most recently mounted one.

Reviewed By: foghina

Differential Revision: D3200203

fb-gh-sync-id: 8ed45fc9b289e8d9c50d3c85926213bd245d3ecc
fbshipit-source-id: 8ed45fc9b289e8d9c50d3c85926213bd245d3ecc

Libraries/AppRegistry/AppRegistry.js

@@ -12,6 +12,7 @@
 'use strict';
 
 var BatchedBridge = require('BatchedBridge');
+var BugReporting = require('BugReporting');
 var ReactNative = require('ReactNative');
 
 var invariant = require('fbjs/lib/invariant');
@@ -79,13 +80,15 @@ var AppRegistry = {
   },
 
   runApplication: function(appKey: string, appParameters: any): void {
-    console.log(
+    const msg =
       'Running application "' + appKey + '" with appParams: ' +
       JSON.stringify(appParameters) + '. ' +
       '__DEV__ === ' + String(__DEV__) +
       ', development-level warning are ' + (__DEV__ ? 'ON' : 'OFF') +
-      ', performance optimizations are ' + (__DEV__ ? 'OFF' : 'ON')
-    );
+      ', performance optimizations are ' + (__DEV__ ? 'OFF' : 'ON');
+    console.log(msg);
+    BugReporting.init();
+    BugReporting.addSource('AppRegistry.runApplication', () => msg);
     invariant(
       runnables[appKey] && runnables[appKey].run,
       'Application ' + appKey + ' has not been registered. This ' +

Libraries/BugReporting/BugReporting.js

@@ -0,0 +1,75 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule BugReporting
+ * @flow
+ */
+'use strict';
+
+const BatchedBridge = require('BatchedBridge');
+const BugReportingNativeModule = require('NativeModules').BugReporting;
+
+type ExtraData = { [key: string]: string };
+type SourceCallback = () => string;
+
+/**
+ * A simple class for collecting bug report data. Components can add sources that will be queried when a bug report
+ * is created via `collectExtraData`. For example, a list component might add a source that provides the list of rows
+ * that are currently visible on screen. Components should also remember to call `remove()` on the object that is
+ * returned by `addSource` when they are unmounted.
+ */
+class BugReporting {
+
+  static _sources: Map<string, SourceCallback> = new Map();
+
+  /**
+   * `init` is called in `AppRegistry.runApplication`, so you shouldn't have to worry about it.
+   */
+  static init() {
+    BatchedBridge.registerCallableModule( // idempotent
+      'BugReporting',
+      BugReporting,
+    );
+  }
+
+  /**
+   * Maps a string key to a simple callback that should return a string payload to be attached
+   * to a bug report. Source callbacks are called when `collectExtraData` is called.
+   *
+   * Returns an object to remove the source when the component unmounts.
+   *
+   * Conflicts trample with a warning.
+   */
+  static addSource(key: string, callback: SourceCallback): {remove: () => void} {
+    if (BugReporting._sources.has(key)) {
+      console.warn(`BugReporting.addSource called multiple times for same key '${key}'`);
+    }
+    BugReporting._sources.set(key, callback);
+    return {remove: () => { BugReporting._sources.delete(key); }};
+  }
+
+  /**
+   * This can be called from a native bug reporting flow, or from JS code.
+   *
+   * If available, this will call `NativeModules.BugReporting.setExtraData(extraData)`
+   * after collecting `extraData`.
+   */
+  static collectExtraData(): ExtraData {
+    const extraData: ExtraData = {};
+    for (const [key, callback] of BugReporting._sources) {
+      extraData[key] = callback();
+    }
+    console.log('BugReporting extraData:', extraData);
+    BugReportingNativeModule &&
+      BugReportingNativeModule.setExtraData &&
+      BugReportingNativeModule.setExtraData(extraData);
+    return extraData;
+  }
+}
+
+module.exports = BugReporting;