feat: return outcome of set and recrypt.

This commits adds a boolean return value from the underlying MMKV library to the JS environment for the set and recrypt calls.

android/src/main/cpp/MmkvHostObject.cpp

@@ -70,18 +70,19 @@ jsi::Value MmkvHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& pro
                                "MMKV::set: First argument ('key') has to be of type string!");
           }
 
+          bool result = false;
           auto keyName = arguments[0].getString(runtime).utf8(runtime);
 
           if (arguments[1].isBool()) {
             // bool
-            instance->set(arguments[1].getBool(), keyName);
+            result = instance->set(arguments[1].getBool(), keyName);
           } else if (arguments[1].isNumber()) {
             // number
-            instance->set(arguments[1].getNumber(), keyName);
+            result = instance->set(arguments[1].getNumber(), keyName);
           } else if (arguments[1].isString()) {
             // string
             auto stringValue = arguments[1].getString(runtime).utf8(runtime);
-            instance->set(stringValue, keyName);
+            result = instance->set(stringValue, keyName);
           } else if (arguments[1].isObject()) {
             // object
             auto object = arguments[1].asObject(runtime);
@@ -91,7 +92,7 @@ jsi::Value MmkvHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& pro
               auto bufferValue = typedArray.getBuffer(runtime);
               mmkv::MMBuffer buffer(bufferValue.data(runtime), bufferValue.size(runtime),
                                     mmkv::MMBufferCopyFlag::MMBufferNoCopy);
-              instance->set(buffer, keyName);
+              result = instance->set(buffer, keyName);
             } else {
               // unknown object
               throw jsi::JSError(
@@ -104,7 +105,7 @@ jsi::Value MmkvHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& pro
                 "MMKV::set: 'value' argument is not of type bool, number, string or buffer!");
           }
 
-          return jsi::Value::undefined();
+          return jsi::Value(result);
         });
   }
 
@@ -269,19 +270,20 @@ jsi::Value MmkvHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& pro
         1, // encryptionKey
         [this](jsi::Runtime& runtime, const jsi::Value& thisValue, const jsi::Value* arguments,
                size_t count) -> jsi::Value {
+          bool result;
           if (arguments[0].isUndefined()) {
             // reset encryption key to "no encryption"
-            instance->reKey(std::string());
+            result = instance->reKey(std::string());
           } else if (arguments[0].isString()) {
             // reKey(..) with new encryption-key
             auto encryptionKey = arguments[0].getString(runtime).utf8(runtime);
-            instance->reKey(encryptionKey);
+            result = instance->reKey(encryptionKey);
           } else {
             throw jsi::JSError(
                 runtime,
                 "First argument ('encryptionKey') has to be of type string (or undefined)!");
           }
-          return jsi::Value::undefined();
+          return jsi::Value(result);
         });
   }
 

example/src/App.tsx

@@ -9,6 +9,7 @@ export default function App() {
   const [text, setText] = React.useState<string>('');
   const [key, setKey] = React.useState<string>('');
   const [keys, setKeys] = React.useState<string[]>([]);
+  const [success, setSuccess] = React.useState<boolean | undefined>();
 
   const [example, setExample] = useMMKVString('yeeeet');
 
@@ -19,7 +20,8 @@ export default function App() {
     }
     try {
       console.log('setting...');
-      storage.set(key, text);
+      const result = storage.set(key, text);
+      setSuccess(result);
       console.log('set.');
     } catch (e) {
       console.error('Error:', e);
@@ -86,6 +88,9 @@ export default function App() {
           onChangeText={setText}
         />
       </View>
+      <View style={styles.row}>
+        {success && <Text>Saved: {success ? 'successfully' : 'failed'}</Text>}
+      </View>
       <Button onPress={save} title="Save to MMKV" />
       <Button onPress={read} title="Read from MMKV" />
     </View>

ios/MmkvHostObject.mm

@@ -82,18 +82,18 @@
             throw jsi::JSError(runtime,
                                "MMKV::set: First argument ('key') has to be of type string!");
           }
-
+          bool result = false;
           auto keyName = convertJSIStringToNSString(runtime, arguments[0].getString(runtime));
           if (arguments[1].isBool()) {
             // Set as boolean
-            [instance setBool:arguments[1].getBool() forKey:keyName];
+            result = [instance setBool:arguments[1].getBool() forKey:keyName];
           } else if (arguments[1].isNumber()) {
             // Set as number (double in JS)
-            [instance setDouble:arguments[1].getNumber() forKey:keyName];
+            result = [instance setDouble:arguments[1].getNumber() forKey:keyName];
           } else if (arguments[1].isString()) {
             // Set as UTF-8 string
             auto stringValue = convertJSIStringToNSString(runtime, arguments[1].getString(runtime));
-            [instance setString:stringValue forKey:keyName];
+            result = [instance setString:stringValue forKey:keyName];
           } else if (arguments[1].isObject()) {
             // object
             auto object = arguments[1].asObject(runtime);
@@ -103,7 +103,7 @@
               auto bufferValue = typedArray.getBuffer(runtime);
               auto data = [[NSData alloc] initWithBytes:bufferValue.data(runtime)
                                                  length:bufferValue.length(runtime)];
-              [instance setData:data forKey:keyName];
+              result = [instance setData:data forKey:keyName];
             } else {
               // unknown object
               throw jsi::JSError(
@@ -115,7 +115,7 @@
                 runtime, "Second argument ('value') has to be of type bool, number or string!");
           }
 
-          return jsi::Value::undefined();
+          return jsi::Value(result);
         });
   }
 
@@ -273,21 +273,22 @@
         1, // encryptionKey
         [this](jsi::Runtime& runtime, const jsi::Value& thisValue, const jsi::Value* arguments,
                size_t count) -> jsi::Value {
+          bool result;
           if (arguments[0].isUndefined()) {
             // reset encryption key to "no encryption"
-            [instance reKey:nil];
+            result = [instance reKey:nil];
           } else if (arguments[0].isString()) {
             // reKey(..) with new encryption-key
             NSString* encryptionKey =
                 convertJSIStringToNSString(runtime, arguments[0].getString(runtime));
             NSData* encryptionKeyBytes = [encryptionKey dataUsingEncoding:NSUTF8StringEncoding];
-            [instance reKey:encryptionKeyBytes];
+            result = [instance reKey:encryptionKeyBytes];
           } else {
             throw jsi::JSError(
                 runtime,
                 "First argument ('encryptionKey') has to be of type string (or undefined)!");
           }
-          return jsi::Value::undefined();
+          return jsi::Value(result);
         });
   }
 

src/MMKV.ts

@@ -29,8 +29,8 @@ export interface MMKVConfiguration {
    * ```ts
    * const temporaryStorage = new MMKV({ path: '/tmp/' })
    * ```
-   * 
-   * _Notice_: On iOS you can set the AppGroup bundle property to share the same storage between your app and its extensions. 
+   *
+   * _Notice_: On iOS you can set the AppGroup bundle property to share the same storage between your app and its extensions.
    * In this case `path` property will be ignored.
    * See more on MMKV configuration [here](https://github.com/Tencent/MMKV/wiki/iOS_tutorial#configuration).
    */
@@ -55,7 +55,7 @@ interface MMKVInterface {
   /**
    * Set a value for the given `key`.
    */
-  set: (key: string, value: boolean | string | number | Uint8Array) => void;
+  set: (key: string, value: boolean | string | number | Uint8Array) => boolean;
   /**
    * Get the boolean value for the given `key`, or `undefined` if it does not exist.
    *
@@ -105,7 +105,7 @@ interface MMKVInterface {
    *
    * Encryption keys can have a maximum length of 16 bytes.
    */
-  recrypt: (key: string | undefined) => void;
+  recrypt: (key: string | undefined) => boolean;
   /**
    * Adds a value changed listener. The Listener will be called whenever any value
    * in this storage instance changes (set or delete).
@@ -179,11 +179,12 @@ export class MMKV implements MMKVInterface {
     }
   }
 
-  set(key: string, value: boolean | string | number | Uint8Array): void {
+  set(key: string, value: boolean | string | number | Uint8Array): boolean {
     const func = this.getFunctionFromCache('set');
-    func(key, value);
+    const result = func(key, value);
 
     this.onValuesChanged([key]);
+    return result;
   }
   getBoolean(key: string): boolean | undefined {
     const func = this.getFunctionFromCache('getBoolean');
@@ -223,7 +224,7 @@ export class MMKV implements MMKVInterface {
 
     this.onValuesChanged(keys);
   }
-  recrypt(key: string | undefined): void {
+  recrypt(key: string | undefined): boolean {
     const func = this.getFunctionFromCache('recrypt');
     return func(key);
   }

src/createMMKV.mock.ts

@@ -7,7 +7,10 @@ export const createMockMMKV = (): NativeMMKV => {
   return {
     clearAll: () => storage.clear(),
     delete: (key) => storage.delete(key),
-    set: (key, value) => storage.set(key, value),
+    set: (key, value) => {
+      storage.set(key, value);
+      return true;
+    },
     getString: (key) => {
       const result = storage.get(key);
       return typeof result === 'string' ? result : undefined;
@@ -28,6 +31,7 @@ export const createMockMMKV = (): NativeMMKV => {
     contains: (key) => storage.has(key),
     recrypt: () => {
       console.warn('Encryption is not supported in mocked MMKV instances!');
+      return true;
     },
   };
 };

src/createMMKV.web.ts

@@ -26,7 +26,7 @@ export const createMMKV = (config: MMKVConfiguration): NativeMMKV => {
   if (config.path != null) {
     throw new Error("MMKV: 'path' is not supported on Web!");
   }
-  
+
   // canUseDOM check prevents spam in Node server environments, such as Next.js server side props.
   if (!hasAccessToLocalStorage() && canUseDOM) {
     console.warn(
@@ -91,6 +91,7 @@ export const createMMKV = (config: MMKVConfiguration): NativeMMKV => {
     delete: (key) => storage().removeItem(prefixedKey(key)),
     set: (key, value) => {
       storage().setItem(prefixedKey(key), value.toString());
+      return true;
     },
     getString: (key) => storage().getItem(prefixedKey(key)) ?? undefined,
     getNumber: (key) => {