From 7b4595ed5e169314ecf6c6389eb5b355a657d570 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E8=91=9B=E4=BA=9A=E8=8A=B3?= Date: Tue, 16 Aug 2022 13:03:30 +0000 Subject: [PATCH] update en/application-dev/reference/apis/js-apis-data-storage.md. Signed-off-by: @ge-yafang MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: 葛亚芳 --- .../reference/apis/js-apis-data-storage.md | 858 ++++++++++-------- 1 file changed, 492 insertions(+), 366 deletions(-) diff --git a/en/application-dev/reference/apis/js-apis-data-storage.md b/en/application-dev/reference/apis/js-apis-data-storage.md index 5f2a2db1ba..7b7178215a 100644 --- a/en/application-dev/reference/apis/js-apis-data-storage.md +++ b/en/application-dev/reference/apis/js-apis-data-storage.md @@ -3,10 +3,9 @@ Lightweight storage provides applications with data processing capability and allows applications to perform lightweight data storage and query. Data is stored in key-value (KV) pairs. Keys are of the string type, and values can be of the number, string, or Boolean type. -> **NOTE**
+> **NOTE** > -> The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version. - +> The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version. @@ -20,10 +19,10 @@ import data_storage from '@ohos.data.storage'; **System capability**: SystemCapability.DistributedDataManager.Preferences.Core -| Name| Type| Readable| Writable| Description| -| -------- | -------- | -------- | -------- | -------- | -| MAX_KEY_LENGTH | string | Yes| No| Maximum length of a key. It must be less than 80 bytes.| -| MAX_VALUE_LENGTH | string | Yes| No| Maximum length of a value. It must be less than 8192 bytes.| +| Name | Type | Readable | Writable | Description | +| ---------------- | ------ | -------- | -------- | ----------------------------------------------------------- | +| MAX_KEY_LENGTH | string | Yes | No | Maximum length of a key. It must be less than 80 bytes. | +| MAX_VALUE_LENGTH | string | Yes | No | Maximum length of a value. It must be less than 8192 bytes. | ## data_storage.getStorageSync @@ -35,25 +34,33 @@ Reads the specified file and loads its data to the **Storage** instance for data **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Return value** - | Type| Description| - | -------- | -------- | - | [Storage](#storage) | **Storage** instance used for data storage operations.| + +| Type | Description | +| ------------------- | ------------------------------------------------------ | +| [Storage](#storage) | **Storage** instance used for data storage operations. | **Example** - ```js - import data_storage from '@ohos.data.storage' - - let path = '/data/storage/el2/database' - let storage = data_storage.getStorageSync(path + '/mystore') - storage.putSync('startup', 'auto') - storage.flushSync() - - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +let storage = data_storage.getStorageSync(path + '/mystore'); +storage.putSync('startup', 'auto'); +storage.flushSync(); +``` ## data_storage.getStorage @@ -65,25 +72,33 @@ Reads the specified file and loads its data to the **Storage** instance for data **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| - | callback | AsyncCallback<[Storage](#storage)> | Yes| Callback used to return the execution result.| + +| Name | Type | Mandatory | Description | +| -------- | ---------------------------------------- | --------- | --------------------------------------------- | +| path | string | Yes | Path of the target file. | +| callback | AsyncCallback<[Storage](#storage)> | Yes | Callback used to return the execution result. | **Example** - ```js - import data_storage from '@ohos.data.storage' - - let path = '/data/storage/el2/database' - data_storage.getStorage(path + '/mystore', function (err, storage) { - if (err) { - console.info("Failed to get the storage. Path: " + path + '/mystore') - return; - } - storage.putSync('startup', 'auto') - storage.flushSync() - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +data_storage.getStorage(path + '/mystore', function (err, storage) { + if (err) { + console.info("Failed to get the storage. path: " + path + '/mystore'); + return; + } + storage.putSync('startup', 'auto'); + storage.flushSync(); +}) +``` ## data_storage.getStorage @@ -95,29 +110,37 @@ Reads the specified file and loads its data to the **Storage** instance for data **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<[Storage](#storage)> | Promise used to return the result.| + +| Type | Description | +| ---------------------------------- | ---------------------------------- | +| Promise<[Storage](#storage)> | Promise used to return the result. | **Example** - ```js - import data_storage from '@ohos.data.storage' - - let path = '/data/storage/el2/database' - - let getPromise = data_storage.getStorage(path + '/mystore') - getPromise.then((storage) => { - storage.putSync('startup', 'auto') - storage.flushSync() - }).catch((err) => { - console.info("Failed to get the storage. Path: " + path + '/mystore') - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +let getPromise = data_storage.getStorage(path + '/mystore'); +getPromise.then((storage) => { + storage.putSync('startup', 'auto'); + storage.flushSync(); +}).catch((err) => { + console.info("Failed to get the storage. path: " + path + '/mystore'); +}) +``` ## data_storage.deleteStorageSync @@ -129,15 +152,25 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Example** - ```js - let path = '/data/storage/el2/database' - data_storage.deleteStorageSync(path + '/mystore') - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +data_storage.deleteStorageSync(path + '/mystore'); +``` ## data_storage.deleteStorage @@ -149,22 +182,32 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------- | +| path | string | Yes | Path of the target file. | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - let path = '/data/storage/el2/database' - data_storage.deleteStorage(path + '/mystore', function (err) { - if (err) { - console.info("Deleted failed with err: " + err) - return - } - console.info("Deleted successfully.") - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +data_storage.deleteStorage(path + '/mystore', function (err) { + if (err) { + console.info("Failed to delete the storage with err: " + err); + return; + } + console.info("Succeeded in deleting the storage."); +}) +``` ## data_storage.deleteStorage @@ -176,25 +219,35 @@ Deletes the singleton **Storage** instance of a file from the memory, and delete **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let path = '/data/storage/el2/database' - let promisedelSt = data_storage.deleteStorage(path + '/mystore') - promisedelSt.then(() => { - console.info("Deleted successfully.") - }).catch((err) => { - console.info("Deleted failed with err: " + err) - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +let promisedelSt = data_storage.deleteStorage(path + '/mystore'); +promisedelSt.then(() => { + console.info("Succeeded in deleting the storage."); +}).catch((err) => { + console.info("Failed to delete the storage with err: " + err); +}) +``` ## data_storage.removeStorageFromCacheSync @@ -206,15 +259,25 @@ Removes the singleton **Storage** instance of a file from the cache. The removed **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Example** - ```js - let path = '/data/storage/el2/database' - data_storage.removeStorageFromCacheSync(path + '/mystore') - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +data_storage.removeStorageFromCacheSync(path + '/mystore'); +``` ## data_storage.removeStorageFromCache @@ -226,22 +289,32 @@ Removes the singleton **Storage** instance of a file from the cache. The removed **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------- | +| path | string | Yes | Path of the target file. | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - let path = '/data/storage/el2/database' - data_storage.removeStorageFromCache(path + '/mystore', function (err) { - if (err) { - console.info("Removed storage from cache failed with err: " + err) - return - } - console.info("Removed storage from cache successfully.") - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +data_storage.removeStorageFromCache(path + '/mystore', function (err) { + if (err) { + console.info("Failed to remove storage from cache with err: " + err); + return; + } + console.info("Succeeded in removing storage from cache."); +}) +``` ## data_storage.removeStorageFromCache @@ -253,25 +326,36 @@ Removes the singleton **Storage** instance of a file from the cache. The removed **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | path | string | Yes| Path of the target file.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------ | +| path | string | Yes | Path of the target file. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| + +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let path = '/data/storage/el2/database' - let promiserevSt = data_storage.removeStorageFromCache(path + '/mystore') - promiserevSt.then(() => { - console.info("Removed storage from cache successfully.") - }).catch((err) => { - console.info("Removed storage from cache failed with err: " + err) - }) - ``` + +```js +import featureAbility from '@ohos.ability.featureAbility'; + +var path; +var context = featureAbility.getContext(); +context.getFilesDir().then((filePath) => { + path = filePath; + console.info("======================>getFilesDirPromsie====================>"); +}); + +let promiserevSt = data_storage.removeStorageFromCache(path + '/mystore') +promiserevSt.then(() => { + console.info("Succeeded in removing storage from cache."); +}).catch((err) => { + console.info("Failed to remove storage from cache with err: " + err); +}) +``` ## Storage @@ -288,21 +372,24 @@ Obtains the value corresponding to a key. If the value is null or not in the def **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| - | defValue | [ValueType](#valuetype) | Yes| Default value to be returned if the value of the specified key does not exist. It can be a number, string, or Boolean value.| + +| Name | Type | Mandatory | Description | +| -------- | ----------------------- | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| defValue | [ValueType](#valuetype) | Yes | Default value to be returned if the value of the specified key does not exist. It can be a number, string, or Boolean value. | **Return value** - | Type| Description| - | -------- | -------- | - | ValueType | Value corresponding to the specified key. If the value is null or not in the default value format, the default value is returned.| + +| Type | Description | +| --------- | ------------------------------------------------------------ | +| ValueType | Value corresponding to the specified key. If the value is null or not in the default value format, the default value is returned. | **Example** - ```js - let value = storage.getSync('startup', 'default') - console.info("The value of startup is " + value) - ``` + +```js +let value = storage.getSync('startup', 'default'); +console.info("The value of startup is " + value); +``` ### get @@ -314,22 +401,24 @@ Obtains the value corresponding to a key. If the value is null or not in the def **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| - | defValue | [ValueType](#valuetype) | Yes| Default value to be returned. It can be a number, string, or Boolean value.| - | callback | AsyncCallback<ValueType> | Yes| Callback used to return the execution result.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------------ | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| defValue | [ValueType](#valuetype) | Yes | Default value to be returned. It can be a number, string, or Boolean value. | +| callback | AsyncCallback<ValueType> | Yes | Callback used to return the execution result. | **Example** - ```js - storage.get('startup', 'default', function(err, value) { - if (err) { - console.info("Get the value of startup failed with err: " + err) - return + +```js +storage.get('startup', 'default', function(err, value) { + if (err) { + console.info("Failed to get the value of startup with err: " + err); + return; } - console.info("The value of startup is " + value) - }) - ``` + console.info("The value of startup is " + value); +}) +``` ### get @@ -342,25 +431,26 @@ Obtains the value corresponding to a key. If the value is null or not in the def **Parameters** -| Name| Type| Mandatory| Description| -| -------- | -------- | -------- | -------- | -| key | string | Yes| Key of the data. It cannot be empty.| -| defValue | [ValueType](#valuetype) | Yes| Default value to be returned. It can be a number, string, or Boolean value.| +| Name | Type | Mandatory | Description | +| -------- | ----------------------- | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| defValue | [ValueType](#valuetype) | Yes | Default value to be returned. It can be a number, string, or Boolean value. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<ValueType> | Promise used to return the result.| + +| Type | Description | +| ------------------------ | ---------------------------------- | +| Promise<ValueType> | Promise used to return the result. | **Example** - ```js - let promiseget = storage.get('startup', 'default') - promiseget.then((value) => { - console.info("The value of startup is " + value) - }).catch((err) => { - console.info("Get the value of startup failed with err: " + err) - }) - ``` +```js +let promiseget = storage.get('startup', 'default'); +promiseget.then((value) => { + console.info("The value of startup is " + value) +}).catch((err) => { + console.info("Failed to get the value of startup with err: " + err); +}) +``` ### putSync @@ -372,15 +462,17 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat **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| New value to store. It can be a number, string, or Boolean value.| + +| Name | Type | Mandatory | Description | +| ----- | ----------------------- | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| value | [ValueType](#valuetype) | Yes | New value to store. It can be a number, string, or Boolean value. | **Example** - ```js - storage.putSync('startup', 'auto') - ``` + +```js +storage.putSync('startup', 'auto') +``` ### put @@ -392,22 +484,24 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat **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| New value to store. It can be a number, string, or Boolean value.| - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| value | [ValueType](#valuetype) | Yes | New value to store. It can be a number, string, or Boolean value. | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - storage.put('startup', 'auto', function (err) { - if (err) { - console.info("Put the value of startup failed with err: " + err) - return - } - console.info("Put the value of startup successfully.") - }) - ``` + +```js +storage.put('startup', 'auto', function (err) { + if (err) { + console.info("Failed to put the value of startup with err: " + err); + return; + } + console.info("Succeeded in putting the value of startup."); +}) +``` ### put @@ -419,25 +513,27 @@ Obtains the **Storage** instance corresponding to the specified file, writes dat **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| New value to store. It can be a number, string, or Boolean value.| + +| Name | Type | Mandatory | Description | +| ----- | ----------------------- | --------- | ------------------------------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| value | [ValueType](#valuetype) | Yes | New value to store. It can be a number, string, or Boolean value. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| + +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let promiseput = storage.put('startup', 'auto') - promiseput.then(() => { - console.info("Put the value of startup successfully.") - }).catch((err) => { - console.info("Put the value of startup failed with err: " + err) - }) - ``` +```js +let promiseput = storage.put('startup', 'auto'); +promiseput.then(() => { + console.info("Succeeded in putting the value of startup."); +}).catch((err) => { + console.info("Failed to put the value of startup with err: " + err); +}) +``` ### hasSync @@ -449,22 +545,25 @@ Checks whether the storage object contains data with a given key. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | **Return value** - | Type| Description| - | -------- | -------- | - | boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.| + +| Type | Description | +| ------- | ------------------------------------------------------------ | +| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise. | **Example** - ```js - let isExist = storage.hasSync('startup') - if (isExist) { - console.info("The key of startup is contained.") - } - ``` + +```js +let isExist = storage.hasSync('startup'); +if (isExist) { + console.info("The key of startup is contained."); +} +``` ### has @@ -476,28 +575,31 @@ Checks whether the storage object contains data with a given key. This API uses **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| - | callback | AsyncCallback<boolean> | Yes| Callback used to return the execution result.| + +| Name | Type | Mandatory | Description | +| -------- | ---------------------------- | --------- | --------------------------------------------- | +| key | string | Yes | Key of the data. It cannot be empty. | +| callback | AsyncCallback<boolean> | Yes | Callback used to return the execution result. | **Return value** - | Type| Description| - | -------- | -------- | - | boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise.| + +| Type | Description | +| ------- | ------------------------------------------------------------ | +| boolean | Returns **true** if the storage object contains data with the specified key; returns **false** otherwise. | **Example** - ```js - storage.has('startup', function (err, isExist) { - if (err) { - console.info("Check the key of startup failed with err: " + err) - return - } - if (isExist) { - console.info("The key of startup is contained.") - } - }) - ``` + +```js +storage.has('startup', function (err, isExist) { + if (err) { + console.info("Failed to check the key of startup with err: " + err); + return; + } + if (isExist) { + console.info("The key of startup is contained."); + } +}) +``` ### has @@ -509,26 +611,29 @@ Checks whether the storage object contains data with a given key. This API uses **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<boolean> | Promise used to return the result.| + +| Type | Description | +| ---------------------- | ---------------------------------- | +| Promise<boolean> | Promise used to return the result. | **Example** - ```js - let promisehas = storage.has('startup') - promisehas.then((isExist) => { - if (isExist) { - console.info("The key of startup is contained.") - } - }).catch((err) => { - console.info("Check the key of startup failed with err: " + err) - }) - ``` + +```js +let promisehas = storage.has('startup') +promisehas.then((isExist) => { + if (isExist) { + console.info("The key of startup is contained."); + } +}).catch((err) => { + console.info("Failed to check the key of startup with err: " + err); +}) +``` ### deleteSync @@ -540,14 +645,16 @@ Deletes data with the specified key from this storage object. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | **Example** - ```js - storage.deleteSync('startup') - ``` + +```js +storage.deleteSync('startup') +``` ### delete @@ -559,21 +666,23 @@ Deletes data with the specified key from this storage object. This API uses an a **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data. It cannot be empty.| - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------------ | +| key | string | Yes | Key of the data. It cannot be empty. | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - storage.delete('startup', function (err) { - if (err) { - console.info("Delete startup key failed with err: " + err) - return - } - console.info("Deleted startup key successfully.") - }) - ``` + +```js +storage.delete('startup', function (err) { + if (err) { + console.info("Failed to delete startup key failed err: " + err); + return; + } + console.info("Succeeded in deleting startup key."); +}) +``` ### delete @@ -585,24 +694,27 @@ Deletes data with the specified key from this storage object. This API uses a pr **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | key | string | Yes| Key of the data.| + +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ---------------- | +| key | string | Yes | Key of the data. | **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| + +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let promisedel = storage.delete('startup') - promisedel.then(() => { - console.info("Deleted startup key successfully.") - }).catch((err) => { - console.info("Delete startup key failed with err: " + err) - }) - ``` + +```js +let promisedel = storage.delete('startup') +promisedel.then(() => { + console.info("Succeeded in deleting startup key."); +}).catch((err) => { + console.info("Failed to delete startup key failed err: " + err); +}) +``` ### flushSync @@ -614,9 +726,10 @@ Saves the modification of this object to the **Storage** instance and synchroniz **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Example** - ```js - storage.flushSync() - ``` + +```js +storage.flushSync() +``` ### flush @@ -628,20 +741,22 @@ Saves the modification of this object to the **Storage** instance and synchroniz **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------- | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - storage.flush(function (err) { - if (err) { - console.info("Flush to file failed with err: " + err) - return - } - console.info("Flushed to file successfully.") - }) - ``` + +```js +storage.flush(function (err) { + if (err) { + console.info("Failed to flush to file with err: " + err); + return; + } + console.info("Succeeded in flushing to file."); +}) +``` ### flush @@ -653,19 +768,21 @@ Saves the modification of this object to the **Storage** instance and synchroniz **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| + +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let promiseflush = storage.flush() - promiseflush.then(() => { - console.info("Flushed to file successfully.") - }).catch((err) => { - console.info("Flush to file failed with err: " + err) - }) - ``` + +```js +let promiseflush = storage.flush(); +promiseflush.then(() => { + console.info("Succeeded in flushing to file."); +}).catch((err) => { + console.info("Failed to flush to file with err: " + err); +}) +``` ### clearSync @@ -677,9 +794,10 @@ Clears this **Storage** object. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Example** - ```js - storage.clearSync() - ``` + +```js +storage.clearSync() +``` ### clear @@ -691,20 +809,22 @@ Clears this **Storage** object. This API uses an asynchronous callback to return **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Mandatory| Description| - | -------- | -------- | -------- | -------- | - | callback | AsyncCallback<void> | Yes| Callback that returns no value.| + +| Name | Type | Mandatory | Description | +| -------- | ------------------------- | --------- | ------------------------------- | +| callback | AsyncCallback<void> | Yes | Callback that returns no value. | **Example** - ```js - storage.clear(function (err) { - if (err) { - console.info("Clear to file failed with err: " + err) - return - } - console.info("Cleared to file successfully.") - }) - ``` + +```js +storage.clear(function (err) { + if (err) { + console.info("Failed to clear the storage with err: " + err); + return; + } + console.info("Succeeded in clearing the storage."); +}) +``` ### clear @@ -716,19 +836,21 @@ Clears this **Storage** object. This API uses a promise to return the result. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Return value** - | Type| Description| - | -------- | -------- | - | Promise<void> | Promise that returns no value.| + +| Type | Description | +| ------------------- | ------------------------------ | +| Promise<void> | Promise that returns no value. | **Example** - ```js - let promiseclear = storage.clear() - promiseclear.then(() => { - console.info("Cleared to file successfully.") - }).catch((err) => { - console.info("Clear to file failed with err: " + err) - }) - ``` + +```js +let promiseclear = storage.clear(); +promiseclear.then(() => { + console.info("Succeeded in clearing the storage."); +}).catch((err) => { + console.info("Failed to clear the storage with err: " + err); +}) +``` ### on('change') @@ -740,20 +862,22 @@ Subscribes to data changes. The **StorageObserver** needs to be implemented. Whe **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Description| - | -------- | -------- | -------- | - | type | string | Event type. The value **change** indicates data change events.| - | callback | Callback<[StorageObserver](#storageobserver)> | Callback used to return data changes.| + +| Name | Type | Description | +| -------- | --------------------------------------------------- | ------------------------------------------------------------ | +| type | string | Event type. The value **change** indicates data change events. | +| callback | Callback<[StorageObserver](#storageobserver)> | Callback used to return data changes. | **Example** - ```js - var observer = function (key) { - console.info("The key of " + key + " changed.") - } - storage.on('change', observer) - storage.putSync('startup', 'auto') - storage.flushSync() // observer will be called. - ``` + +```js +var observer = function (key) { + console.info("The key of " + key + " changed."); +} +storage.on('change', observer); +storage.putSync('startup', 'auto'); +storage.flushSync(); // observer will be called. +``` ### off('change') @@ -765,27 +889,29 @@ Unsubscribes from data changes. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core **Parameters** - | Name| Type| Description| - | -------- | -------- | -------- | - | type | string | Event type. The value **change** indicates data change events.| - | callback | Callback<[StorageObserver](#storageobserver)> | Callback used to return data changes.| + +| Name | Type | Description | +| -------- | --------------------------------------------------- | ------------------------------------------------------------ | +| type | string | Event type. The value **change** indicates data change events. | +| callback | Callback<[StorageObserver](#storageobserver)> | Callback used to return data changes. | **Example** - ```js - var observer = function (key) { - console.info("The key of " + key + " changed.") - } - storage.off('change', observer) - ``` + +```js +var observer = function (key) { + console.info("The key of " + key + " changed."); +} +storage.off('change', observer); +``` ## StorageObserver **System capability**: SystemCapability.DistributedDataManager.Preferences.Core -| Name| Type| Mandatory| Description| -| -------- | -------- | -------- | -------- | -| key | string | No| Data changed.| +| Name | Type | Mandatory | Description | +| ---- | ------ | --------- | ------------- | +| key | string | No | Data changed. | ## ValueType @@ -793,8 +919,8 @@ Enumerates the value types. **System capability**: SystemCapability.DistributedDataManager.Preferences.Core -| Type | Description | -| ------- | -------------------- | -| number | The value is a number. | -| string | The value is a string. | -| boolean | The value is of Boolean type.| +| Type | Description | +| ------- | ----------------------------- | +| number | The value is a number. | +| string | The value is a string. | +| boolean | The value is of Boolean type. | \ No newline at end of file -- GitLab