fixed 3fba769f from https://gitee.com/Annie_wang/docs/pulls/9993

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

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

@@ -40,7 +40,7 @@ Obtains a **Preferences** instance. This API uses an asynchronous callback to re
 | -------- | ------------------------------------------------ | ---- | ------------------------------------------------------------ |
 | context  | [Context](js-apis-ability-context.md)            | Yes  | Application context.                                                |
 | name     | string                                           | Yes  | Name of the **Preferences** instance.                                     |
-| callback | AsyncCallback<[Preferences](#preferences)> | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **object** is the **Preferences** instance obtained. Otherwise, **err** is an error code.|
+| callback | AsyncCallback<[Preferences](#preferences)> | Yes  | Callback invoked to return the result. If the operation is successful, **err** is undefined and the **Preferences** instance obtained is returned. Otherwise, **err** is an error code.|
 
 **Example**
 
@@ -66,12 +66,14 @@ Obtains a **Preferences** instance. This API uses a promise to return the result
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name | Type                                 | Mandatory| Description                   |
-| ------- | ------------------------------------- | ---- | -------------------------- |
+| ------- | ------------------------------------- | ---- | ----------------------- |
 | context | [Context](js-apis-ability-context.md) | Yes  | Application context.           |
 | name    | string                                | Yes  | Name of the **Preferences** instance.|
 
 **Return value**
+
 | Type                                      | Description                              |
 | ------------------------------------------ | ---------------------------------- |
 | Promise<[Preferences](#preferences)> | Promise used to return the **Preferences** instance obtained.|
@@ -103,6 +105,7 @@ The deleted **Preferences** instance cannot be used for data operations. Otherwi
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                                 | Mandatory| Description                                                |
 | -------- | ------------------------------------- | ---- | ---------------------------------------------------- |
 | context  | [Context](js-apis-ability-context.md) | Yes  | Application context.                                        |
@@ -110,6 +113,7 @@ The deleted **Preferences** instance cannot be used for data operations. Otherwi
 | callback | AsyncCallback<void>             | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
 
 **Example**
+
 ```js
 data_preferences.deletePreferences(this.context, 'mystore', function (err) {
     if (err) {
@@ -134,17 +138,20 @@ The deleted **Preferences** instance cannot be used for data operations. Otherwi
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name | Type                                 | Mandatory| Description                   |
-| ------- | ------------------------------------- | ---- | -------------------------- |
+| ------- | ------------------------------------- | ---- | ----------------------- |
 | context | [Context](js-apis-ability-context.md) | Yes  | Application context.           |
 | name    | string                                | Yes  | Name of the **Preferences** instance to delete.|
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise<void> | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = data_preferences.deletePreferences(this.context, 'mystore')
 promise.then(() => {
@@ -166,6 +173,7 @@ The removed **Preferences** instance cannot be used for data operations. Otherwi
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                                 | Mandatory| Description                                                |
 | -------- | ------------------------------------- | ---- | ---------------------------------------------------- |
 | context  | [Context](js-apis-ability-context.md) | Yes  | Application context.                            |
@@ -173,6 +181,7 @@ The removed **Preferences** instance cannot be used for data operations. Otherwi
 | callback | AsyncCallback<void>             | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
 
 **Example**
+
 ```js
 data_preferences.removePreferencesFromCache(this.context, 'mystore', function (err) {
     if (err) {
@@ -195,17 +204,20 @@ The removed **Preferences** instance cannot be used for data operations. Otherwi
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name | Type                                 | Mandatory| Description                   |
-| ------- | ------------------------------------- | ---- | -------------------------- |
+| ------- | ------------------------------------- | ---- | ----------------------- |
 | context | [Context](js-apis-ability-context.md) | Yes  | Application context.           |
 | name    | string                                | Yes  | Name of the **Preferences** instance to remove.|
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise<void> | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = data_preferences.removePreferencesFromCache(this.context, 'mystore')
 promise.then(() => {
@@ -232,6 +244,7 @@ Obtains the value of a key. This API uses an asynchronous callback to return the
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                                        | Mandatory| Description                                                        |
 | -------- | -------------------------------------------- | ---- | ------------------------------------------------------------ |
 | key      | string                                       | Yes  | Key of the data to obtain. It cannot be empty.                             |
@@ -260,6 +273,7 @@ Obtains the value of a key. This API uses a promise to return the result. If the
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
  **Parameters**
+ 
 | Name  | Type                   | Mandatory| Description                                                        |
 | -------- | ----------------------- | ---- | ------------------------------------------------------------ |
 | key      | string                  | Yes  | Key of the data to obtain. It cannot be empty.                             |
@@ -272,6 +286,7 @@ Obtains the value of a key. This API uses a promise to return the result. If the
 | Promise<[ValueType](#valuetype)&gt; | Promise used to return the value obtained.|
 
 **Example**
+
 ```js
 let promise = preferences.get('startup', 'default');
 promise.then((data) => {
@@ -290,6 +305,7 @@ Obtains an **Object** instance that contains all KV pairs. This API uses an asyn
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                       | Mandatory| Description                                                        |
 | -------- | --------------------------- | ---- | ------------------------------------------------------------ |
 | callback | AsyncCallback&lt;Object&gt; | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined** and **value** is the **Object** instance obtained. Otherwise, **err** is an error code.|
@@ -318,11 +334,13 @@ Obtains an **Object** instance that contains all KV pairs. This API uses a promi
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Return value**
+
 | Type                 | Description                                       |
 | --------------------- | ------------------------------------------- |
 | Promise&lt;Object&gt; | Promise used to return the **Object** instance obtained.|
 
 **Example**
+
 ```js
 let promise = preferences.getAll();
 promise.then((value) => {
@@ -343,6 +361,7 @@ Writes data to this **Preferences** instance. This API uses an asynchronous call
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                     | Mandatory| Description                                                        |
 | -------- | ------------------------- | ---- | ------------------------------------------------------------ |
 | key      | string                    | Yes  | Key of the data. It cannot be empty.                               |
@@ -350,6 +369,7 @@ Writes data to this **Preferences** instance. This API uses an asynchronous call
 | callback | AsyncCallback&lt;void&gt; | Yes  | Callback invoked to return the result. If the operation is successful, **err** is undefined. Otherwise, **err** is an error code.    |
 
 **Example**
+
 ```js
 preferences.put('startup', 'auto', function (err) {
     if (err) {
@@ -370,17 +390,20 @@ Writes data to this **Preferences** instance. This API uses a promise to return
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name| Type                   | Mandatory| Description                                                        |
 | ------ | ----------------------- | ---- | ------------------------------------------------------------ |
 | key    | string                  | Yes  | Key of the data. It cannot be empty.                               |
 | value  | [ValueType](#valuetype) | Yes  | Value to write. The value can be a number, a string, a Boolean value, or an array of numbers, strings, or Boolean values.|
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise&lt;void&gt; | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = preferences.put('startup', 'auto');
 promise.then(() => {
@@ -400,12 +423,14 @@ Checks whether this **Preferences** instance contains a KV pair of the given key
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                        | Mandatory| Description                                                        |
 | -------- | ---------------------------- | ---- | ------------------------------------------------------------ |
 | key      | string                       | Yes  | Key of the data to check. It cannot be empty.                             |
 | callback | AsyncCallback&lt;boolean&gt; | Yes  | Callback invoked to return the result. If the **Preferences** instance contains the KV pair, **true** will be returned. Otherwise, **false** will be returned.|
 
 **Example**
+
 ```js
 preferences.has('startup', function (err, isExist) {
     if (err) {
@@ -430,11 +455,13 @@ Checks whether this **Preferences** instance contains data with the given key. T
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name| Type  | Mandatory| Description                           |
 | ------ | ------ | ---- | ------------------------------- |
 | key    | string | Yes  | Key of the data to check. It cannot be empty.|
 
 **Return value**
+
 | Type                  | Description                                                        |
 | ---------------------- | ------------------------------------------------------------ |
 | Promise&lt;boolean&gt; | Promise used to return the result. If the **Preferences** instance contains the KV pair, **true** will be returned. Otherwise, **false** will be returned.|
@@ -464,12 +491,14 @@ Deletes a KV pair from this **Preferences** instance. This API uses an asynchron
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                     | Mandatory| Description                                                |
 | -------- | ------------------------- | ---- | ---------------------------------------------------- |
 | key      | string                    | Yes  | Key of the KV pair to delete. It cannot be empty.                     |
 | callback | AsyncCallback&lt;void&gt; | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
 
 **Example**
+
 ```js
 preferences.delete('startup', function (err) {
     if (err) {
@@ -490,16 +519,19 @@ Deletes a KV pair from this **Preferences** instance. This API uses a promise to
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name| Type  | Mandatory| Description                           |
 | ------ | ------ | ---- | ------------------------------- |
 | key    | string | Yes  | Key of the KV pair to delete. It cannot be empty.|
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise&lt;void&gt; | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = preferences.delete('startup');
 promise.then(() => {
@@ -514,16 +546,18 @@ promise.then(() => {
 
 flush(callback: AsyncCallback&lt;void&gt;): void
 
-Saves the data of the **Preferences** instance to a file asynchronously. This API uses an asynchronous callback to return the result.
+Asynchronously stores data of this **Preferences** instance to its persistent file. This API uses a asynchronous callback to return the result.
 
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                     | Mandatory| Description                                                |
 | -------- | ------------------------- | ---- | ---------------------------------------------------- |
 | callback | AsyncCallback&lt;void&gt; | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
 
 **Example**
+
 ```js
 preferences.flush(function (err) {
     if (err) {
@@ -539,16 +573,18 @@ preferences.flush(function (err) {
 
 flush(): Promise&lt;void&gt;
 
-Saves the data of the **Preferences** instance to a file asynchronously. This API uses a promise to return the result.
+Asynchronously stores data of this **Preferences** instance to its persistent file. This API uses a promise to return the result.
 
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise&lt;void&gt; | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = preferences.flush();
 promise.then(() => {
@@ -568,11 +604,13 @@ Clears this **Preferences** instance. This API uses an asynchronous callback to
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                     | Mandatory| Description                                                |
 | -------- | ------------------------- | ---- | ---------------------------------------------------- |
 | callback | AsyncCallback&lt;void&gt; | Yes  | Callback invoked to return the result. If the operation is successful, **err** is **undefined**. Otherwise, **err** is an error code.|
 
 **Example**
+
 ```js
 preferences.clear(function (err) {
     if (err) {
@@ -593,11 +631,13 @@ Clears this **Preferences** instance. This API uses a promise to return the resu
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Return value**
+
 | Type               | Description                     |
 | ------------------- | ------------------------- |
 | Promise&lt;void&gt; | Promise that returns no value.|
 
 **Example**
+
 ```js
 let promise = preferences.clear()
 promise.then(() => {
@@ -617,56 +657,14 @@ Subscribes to data changes. A callback will be triggered to return the new value
 **System capability**: SystemCapability.DistributedDataManager.Preferences.Core
 
 **Parameters**
+
 | Name  | Type                            | Mandatory| Description                                    |
 | -------- | -------------------------------- | ---- | ---------------------------------------- |
 | type     | string                           | Yes  | Event type to subscribe to. The value **change** indicates data change events.|
 | callback | Callback&lt;{ key : string }&gt; | Yes  | Callback invoked to return data changes.                          |
 
 **Example**
-```js
-data_preferences.getPreferences(this.context, 'mystore', function (err, preferences) {
-    if (err) {
-        console.info("Failed to get the preferences.");
-        return;
-    }
-    var observer = function (key) {
-        console.info("The key " + key + " changed.");
-    }
-    preferences.on('change', observer);
-    preferences.put('startup', 'auto', function (err) {
-        if (err) {
-            console.info("Failed to put the value of 'startup'. Cause: " + err);
-            return;
-        }
-        console.info("Put the value of 'startup' successfully.");
-
-        preferences.flush(function (err) {
-            if (err) {
-                console.info("Failed to flush data. Cause: " + err);
-                return;
-            }
-            console.info("Flushed data successfully."); // The observer will be called.
-        })
-    })
-})
-```
-
 
-### off('change')
-
-off(type: 'change', callback?: Callback&lt;{ key : string }&gt;): void
-
-Unsubscribes from data changes.
-
-**System capability**: SystemCapability.DistributedDataManager.Preferences.Core
-
-**Parameters**
-| Name  | Type                            | Mandatory| Description                                      |
-| -------- | -------------------------------- | ---- | ------------------------------------------ |
-| type     | string                           | Yes  | Event type to unsubscribe from. The value **change** indicates data change events.  |
-| callback | Callback&lt;{ key : string }&gt; | No  | Callback to unregister. If this parameter is left blank, the callbacks used to subscribing to all data changes will be unregistered.|
-
-**Example**
 ```js
 data_preferences.getPreferences(this.context, 'mystore', function (err, preferences) {
     if (err) {