update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/application-dev/reference/apis/js-apis-distributed-data.md

@@ -61,7 +61,7 @@ export default class MyAbilityStage extends AbilityStage {
         console.log("Failed to create KVManager: " + JSON.stringify(err));
         return;
       }
-      console.log("Created KVManager");
+      console.log("Created KVManager successfully");
       kvManager = manager;
     });
   }
@@ -89,7 +89,7 @@ export default class MyAbilityStage extends AbilityStage {
         console.log("Failed to create KVManager: " + JSON.stringify(err));
         return;
       }
-      console.log("Created KVManager");
+      console.log("Created KVManager successfully");
       kvManager = manager;
     });
   }
@@ -139,7 +139,7 @@ export default class MyAbilityStage extends AbilityStage {
         console.log("Failed to create KVManager: " + JSON.stringify(err));
         return;
       }
-      console.log("Created KVManager");
+      console.log("Created KVManager successfully");
       kvManager = manager;
     });
   }
@@ -167,7 +167,7 @@ export default class MyAbilityStage extends AbilityStage {
         console.log("Failed to create KVManager: " + JSON.stringify(err));
         return;
       }
-      console.log("Created KVManager");
+      console.log("Created KVManager successfully");
       kvManager = manager;
     });
   }
@@ -606,7 +606,7 @@ try {
 
 off(event: 'distributedDataServiceDie', deathCallback?: Callback<void>): void
 
-Unsubscribes from the service status changes.
+Unsubscribes from service status changes.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.DistributedKVStore
 
@@ -2393,7 +2393,7 @@ Subscribes to data change notifications of the specified type.
 | -----  | ------  | ----  | ----------------------- |
 | event  |string  | Yes   |Event to subscribe to. The value is **dataChange**, which indicates data changes.      |
 | type  |[SubscribeType](#subscribetype) | Yes   |Type of data changes.    |
-| listener |Callback<[ChangeNotification](#changenotification)> | Yes   |Callback used to return the data changes.|
+| listener |Callback<[ChangeNotification](#changenotification)> | Yes   |Callback used to return data changes.|
 
 **Example**
 
@@ -2442,25 +2442,34 @@ Unsubscribes from data change notifications.
 | Name | Type| Mandatory | Description                   |
 | -----  | ------  | ----  | ----------------------- |
 | event  |string  | Yes   |Event to unsubscribe from. The value is **dataChange**, which indicates data changes.      |
-| listener |Callback<[ChangeNotification](#changenotification)> |No   |Callback used to return the data changes.|
+| listener |Callback<[ChangeNotification](#changenotification)> |No   |Callback used to return data changes.|
 
 **Example**
 
 ```js
 let kvStore;
-kvStore.on('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
-kvStore.off('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
+class KvstoreModel {
+    call(data) {
+        console.log("dataChange: " + data);
+    }
+    subscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
+        }
+    }
+    unsubscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.off('dataChange', this.call);
+        }
+    }
+}
 ```
 
 ### off('syncComplete')<sup>9+</sup>
 
 off(event: 'syncComplete', syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void
 
-Unsubscribes from data change events. This API uses a synchronous callback to return the result.
+Unsubscribes from data change events. This API returns the result synchronously.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -2475,14 +2484,20 @@ Unsubscribes from data change events. This API uses a synchronous callback to re
 
 ```js
 let kvStore;
-try {
-    const func = function (data) {
-        console.log('syncComplete ' + data)
-    };
-    kvStore.on('syncComplete', func);
-    kvStore.off('syncComplete', func);
-}catch(e) {
-    console.log('syncComplete e ' + e);
+class KvstoreModel {
+    call(data) {
+        console.log("syncComplete: " + data);
+    }
+    subscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.on('syncComplete', this.call);
+        }
+    }
+    unsubscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.off('syncComplete', this.call);
+        }
+    }
 }
 ```
 
@@ -4047,7 +4062,7 @@ try {
 
 on(event: 'syncComplete', syncCallback: Callback&lt;Array&lt;[string, number]&gt;&gt;): void
 
-Subscribes to the data synchronization complete events.
+Subscribes to data synchronization complete events.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -4056,7 +4071,7 @@ Subscribes to the data synchronization complete events.
 | Name | Type| Mandatory | Description                   |
 | -----  | ------   | ----  | ----------------------- |
 | event  |string   | Yes   |Event to subscribe to. The value is **syncComplete**, which indicates completion of a data synchronization.   |
-| syncCallback  |Callback&lt;Array&lt;[string, number]&gt;&gt;   | Yes   |Callback called to return the synchronization result.   |
+| syncCallback  |Callback&lt;Array&lt;[string, number]&gt;&gt;   | Yes   |Callback used to return the synchronization result.   |
 
 **Example**
 
@@ -4083,7 +4098,7 @@ try {
 
 off(event: 'syncComplete', syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void
 
-Unsubscribes from the data synchronization complete events.
+Unsubscribes from data synchronization complete events.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -4098,14 +4113,20 @@ Unsubscribes from the data synchronization complete events.
 
 ```js
 let kvStore;
-try {
-    const func = function (data) {
-        console.log('syncComplete ' + data)
-    };
-    kvStore.on('syncComplete', func);
-    kvStore.off('syncComplete', func);
-}catch(e) {
-    console.log('syncComplete e ' + e);
+class KvstoreModel {
+    call(data) {
+        console.log("syncComplete: " + data);
+    }
+    subscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.on('syncComplete', this.call);
+        }
+    }
+    unsubscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.off('syncComplete', this.call);
+        }
+    }
 }
 ```
 
@@ -4139,7 +4160,7 @@ kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_LOCAL, fun
 
 off(event:'dataChange', listener?: Callback&lt;ChangeNotification&gt;): void
 
-Unsubscribes from the data change events. This API returns the result synchronously.
+Unsubscribes from data change events. This API returns the result synchronously.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -4154,12 +4175,21 @@ Unsubscribes from the data change events. This API returns the result synchronou
 
 ```js
 let kvStore;
-kvStore.on('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
-kvStore.off('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
+class KvstoreModel {
+    call(data) {
+        console.log("dataChange: " + data);
+    }
+    subscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
+        }
+    }
+    unsubscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.off('dataChange', this.call);
+        }
+    }
+}
 ```
 ### sync<sup>7+</sup>
 
@@ -5542,7 +5572,7 @@ try {
 
 on(event: 'syncComplete', syncCallback: Callback&lt;Array&lt;[string, number]&gt;&gt;): void
 
-Subscribes to the data synchronization complete events.
+Subscribes to data synchronization complete events.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -5578,7 +5608,7 @@ try {
 
 off(event: 'syncComplete', syncCallback?: Callback&lt;Array&lt;[string, number]&gt;&gt;): void
 
-Unsubscribes from the synchronization complete events. This API returns the result synchronously.
+Unsubscribes from synchronization complete events. This API returns the result synchronously.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -5593,14 +5623,20 @@ Unsubscribes from the synchronization complete events. This API returns the resu
 
 ```js
 let kvStore;
-try {
-    const func = function (data) {
-        console.log('syncComplete ' + data)
-    };
-    kvStore.on('syncComplete', func);
-    kvStore.off('syncComplete', func);
-}catch(e) {
-    console.log('syncComplete e ' + e);
+class KvstoreModel {
+    call(data) {
+        console.log("syncComplete: " + data);
+    }
+    subscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.on('syncComplete', this.call);
+        }
+    }
+    unsubscribeSyncComplete() {
+        if (kvStore != null) {
+            kvStore.off('syncComplete', this.call);
+        }
+    }
 }
 ```
 
@@ -5618,7 +5654,7 @@ Subscribes to data changes of the specified type. This API returns the result sy
 | -----  | ------  | ----  | ----------------------- |
 | event  |string  | Yes   |Event to subscribe to. The value is **dataChange**, which indicates data changes.      |
 | type  |[SubscribeType](#subscribetype) | Yes   |Subscription type.    |
-| listener |Callback&lt;[ChangeNotification](#changenotification)&gt; | Yes   |Callback used to return the result.|
+| listener |Callback&lt;[ChangeNotification](#changenotification)&gt; | Yes   |Callback used to return data changes.|
 
 **Example**
 
@@ -5634,7 +5670,7 @@ kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_LOCAL, fun
 
 off(event:'dataChange', listener?: Callback&lt;ChangeNotification&gt;): void
 
-Unsubscribes from the data change events. This API returns the result synchronously.
+Unsubscribes from data change events. This API returns the result synchronously.
 
 **System capability**: SystemCapability.DistributedDataManager.KVStore.Core
 
@@ -5643,18 +5679,27 @@ Unsubscribes from the data change events. This API returns the result synchronou
 | Name | Type| Mandatory | Description                   |
 | -----  | ------  | ----  | ----------------------- |
 | event  |string  | Yes   |Event to unsubscribe from. The value is **dataChange**, which indicates data changes.      |
-| listener |Callback&lt;[ChangeNotification](#changenotification)&gt; |No   |Callback used to return the result.|
+| listener |Callback&lt;[ChangeNotification](#changenotification)&gt; |No   |Callback used to return data changes.|
 
 **Example**
 
 ```js
 let kvStore;
-kvStore.on('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
-kvStore.off('dataChange', function (data) {
-    console.log("callback call data: " + data);
-});
+class KvstoreModel {
+    call(data) {
+        console.log("dataChange: " + data);
+    }
+    subscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.on('dataChange', distributedData.SubscribeType.SUBSCRIBE_TYPE_REMOTE, this.call);
+        }
+    }
+    unsubscribeDataChange() {
+        if (kvStore != null) {
+            kvStore.off('dataChange', this.call);
+        }
+    }
+}
 ```
 
 ## SyncMode
@@ -5668,4 +5713,3 @@ Enumerates the synchronization modes.
 | PULL_ONLY  |0          |Pull data from the peer end to the local end only.|
 | PUSH_ONLY  |1          |Push data from the local end to the peer end only.|
 | PUSH_PULL  |2          |Push data from the local end to the peer end and then pull data from the peer end to the local end.|
-