Flow support from ifsnow/feature/support-flow

Flow support

Author: krizzu

example/src/examples/GetSet.js

@@ -15,12 +15,12 @@ import AsyncStorage from '@react-native-community/async-storage';
 
 type Props = {};
 type State = {
-  storedNumber: number,
+  storedNumber: string,
   needRestart: boolean,
 };
 export default class GetSet extends Component<Props, State> {
   state = {
-    storedNumber: -1,
+    storedNumber: '',
     needRestart: false,
   };
 
@@ -34,8 +34,8 @@ export default class GetSet extends Component<Props, State> {
   }
 
   storeRandom = async () => {
-    const randomNum = Math.round(Math.random() * 100);
-    await AsyncStorage.setItem(STORAGE_KEY, `${randomNum}`);
+    const randomNum = Math.round(Math.random() * 100).toString();
+    await AsyncStorage.setItem(STORAGE_KEY, randomNum);
 
     this.setState({storedNumber: randomNum, needRestart: true});
   };

lib/AsyncStorage.js

@@ -5,8 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  * @format
- * @noflow
- * @flow-weak
+ * @flow
  * @jsdoc
  */
 
@@ -21,6 +20,21 @@ const RCTAsyncStorage =
   NativeModules.RNC_AsyncSQLiteDBStorage ||
   NativeModules.AsyncLocalStorage;
 
+type ReadOnlyArrayString = $ReadOnlyArray<string>;
+
+type MultiGetCallbackFunction = (
+  errors: ?$ReadOnlyArray<Error>,
+  result: ?$ReadOnlyArray<ReadOnlyArrayString>,
+) => void;
+
+type MultiRequest = {|
+  keys: $ReadOnlyArray<string>,
+  callback: ?MultiGetCallbackFunction,
+  keyIndex: number,
+  resolve: ?(result?: Promise<?$ReadOnlyArray<ReadOnlyArrayString>>) => void,
+  reject: ?(error?: any) => void,
+|};
+
 /**
  * `AsyncStorage` is a simple, unencrypted, asynchronous, persistent, key-value
  * storage system that is global to the app.  It should be used instead of
@@ -29,7 +43,7 @@ const RCTAsyncStorage =
  * See http://facebook.github.io/react-native/docs/asyncstorage.html
  */
 const AsyncStorage = {
-  _getRequests: ([]: Array<any>),
+  _getRequests: ([]: Array<MultiRequest>),
   _getKeys: ([]: Array<string>),
   _immediate: (null: ?number),
 
@@ -40,8 +54,8 @@ const AsyncStorage = {
    */
   getItem: function(
     key: string,
-    callback?: ?(error: ?Error, result: ?string) => void,
-  ): Promise {
+    callback?: ?(error: ?Error, result: string | null) => void,
+  ): Promise<string | null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiGet([key], function(errors, result) {
         // Unpack result to get value from [[key,value]]
@@ -66,7 +80,7 @@ const AsyncStorage = {
     key: string,
     value: string,
     callback?: ?(error: ?Error) => void,
-  ): Promise {
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiSet([[key, value]], function(errors) {
         const errs = convertErrors(errors);
@@ -88,7 +102,7 @@ const AsyncStorage = {
   removeItem: function(
     key: string,
     callback?: ?(error: ?Error) => void,
-  ): Promise {
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiRemove([key], function(errors) {
         const errs = convertErrors(errors);
@@ -114,7 +128,7 @@ const AsyncStorage = {
     key: string,
     value: string,
     callback?: ?(error: ?Error) => void,
-  ): Promise {
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiMerge([[key, value]], function(errors) {
         const errs = convertErrors(errors);
@@ -135,12 +149,13 @@ const AsyncStorage = {
    *
    * See http://facebook.github.io/react-native/docs/asyncstorage.html#clear
    */
-  clear: function(callback?: ?(error: ?Error) => void): Promise {
+  clear: function(callback?: ?(error: ?Error) => void): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.clear(function(error) {
-        callback && callback(convertError(error));
-        if (error && convertError(error)) {
-          reject(convertError(error));
+        const err = convertError(error);
+        callback && callback(err);
+        if (err) {
+          reject(err);
         } else {
           resolve(null);
         }
@@ -154,13 +169,14 @@ const AsyncStorage = {
    * See http://facebook.github.io/react-native/docs/asyncstorage.html#getallkeys
    */
   getAllKeys: function(
-    callback?: ?(error: ?Error, keys: ?Array<string>) => void,
-  ): Promise {
+    callback?: ?(error: ?Error, keys: ?ReadOnlyArrayString) => void,
+  ): Promise<ReadOnlyArrayString> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.getAllKeys(function(error, keys) {
-        callback && callback(convertError(error), keys);
-        if (error) {
-          reject(convertError(error));
+        const err = convertError(error);
+        callback && callback(err, keys);
+        if (err) {
+          reject(err);
         } else {
           resolve(keys);
         }
@@ -223,16 +239,16 @@ const AsyncStorage = {
    */
   multiGet: function(
     keys: Array<string>,
-    callback?: ?(errors: ?Array<Error>, result: ?Array<Array<string>>) => void,
-  ): Promise {
+    callback?: ?MultiGetCallbackFunction,
+  ): Promise<?$ReadOnlyArray<ReadOnlyArrayString>> {
     if (!this._immediate) {
       this._immediate = setImmediate(() => {
         this._immediate = null;
         this.flushGetRequests();
       });
     }
 
-    const getRequest = {
+    const getRequest: MultiRequest = {
       keys: keys,
       callback: callback,
       // do we need this?
@@ -265,8 +281,8 @@ const AsyncStorage = {
    */
   multiSet: function(
     keyValuePairs: Array<Array<string>>,
-    callback?: ?(errors: ?Array<Error>) => void,
-  ): Promise {
+    callback?: ?(errors: ?$ReadOnlyArray<?Error>) => void,
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiSet(keyValuePairs, function(errors) {
         const error = convertErrors(errors);
@@ -287,8 +303,8 @@ const AsyncStorage = {
    */
   multiRemove: function(
     keys: Array<string>,
-    callback?: ?(errors: ?Array<Error>) => void,
-  ): Promise {
+    callback?: ?(errors: ?$ReadOnlyArray<?Error>) => void,
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiRemove(keys, function(errors) {
         const error = convertErrors(errors);
@@ -312,8 +328,8 @@ const AsyncStorage = {
    */
   multiMerge: function(
     keyValuePairs: Array<Array<string>>,
-    callback?: ?(errors: ?Array<Error>) => void,
-  ): Promise {
+    callback?: ?(errors: ?$ReadOnlyArray<?Error>) => void,
+  ): Promise<null> {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiMerge(keyValuePairs, function(errors) {
         const error = convertErrors(errors);
@@ -334,19 +350,20 @@ if (!RCTAsyncStorage.multiMerge) {
   delete AsyncStorage.multiMerge;
 }
 
-function convertErrors(errs) {
+function convertErrors(errs): ?$ReadOnlyArray<?Error> {
   if (!errs) {
     return null;
   }
   return (Array.isArray(errs) ? errs : [errs]).map(e => convertError(e));
 }
 
-function convertError(error) {
+function convertError(error): ?Error {
   if (!error) {
     return null;
   }
   const out = new Error(error.message);
-  out.key = error.key; // flow doesn't like this :(
+  // $FlowFixMe: adding custom properties to error.
+  out.key = error.key;
   return out;
 }