1# Want 2 3Want is a carrier for information transfer between objects (application components). Want can be used as a parameter of [startAbility](js-apis-inner-application-uiAbilityContext.md#uiabilitycontextstartability) to specify a startup target and information that needs to be carried during startup, for example, **bundleName** and **abilityName**, which respectively indicate the bundle name of the target ability and the ability name in the bundle. When ability A needs to start ability B and transfer some data to ability B, it can use Want a carrier to transfer the data. 4 5> **NOTE** 6> 7> The APIs of this module are supported since API version 6 and deprecated since API version 9. You are advised to use [@ohos.app.ability.Want](js-apis-app-ability-want.md) instead. Newly added APIs will be marked with a superscript to indicate their earliest API version. 8 9**System capability**: SystemCapability.Ability.AbilityBase 10 11| Name | Type | Mandatory| Description | 12| ----------- | -------------------- | ---- | ------------------------------------------------------------ | 13| deviceId | string | No | ID of the device running the ability. | 14| bundleName | string | No | Bundle name. If both **bundleName** and **abilityName** are specified in a **Want**, the **Want** can directly match the specified ability.| 15| abilityName | string | No | Name of the ability. If both **bundleName** and **abilityName** are specified in a **Want** object, the **Want** object can match a specific ability. The value of **abilityName** must be unique in an application.| 16| uri | string | No | URI. If **uri** is specified in a **Want** object, the **Want** object will match the specified URI information, including **scheme**, **schemeSpecificPart**, **authority**, and **path**.| 17| type | string | No | MIME type, that is, the type of the file to open, for example, **'text/xml'** and **'image/*'**. For details about the MIME type definition, see https://www.iana.org/assignments/media-types/media-types.xhtml?utm_source=ld246.com. | 18| flags | number | No | How the **Want** object will be handled. By default, numbers are passed in. For details, see [flags](js-apis-app-ability-wantConstant.md#wantconstantflags). | 19| action | string | No | Action to take, such as viewing and sharing application details. In implicit Want, you can define this field and use it together with **uri** or **parameters** to specify the operation to be performed on the data. | 20| parameters | {[key: string]: Object} | No | Want parameters in the form of custom key-value (KV) pairs. By default, the following keys are carried:<br>- **ohos.aafwk.callerPid**: PID of the caller.<br>**ohos.aafwk.param.callerToken**: token of the caller.<br>- **ohos.aafwk.param.callerUid**: UID in [bundleInfo](js-apis-bundle-BundleInfo.md#bundleinfo-1), that is, the application UID in the bundle information.<br>- **component.startup.newRules**: whether to enable the new control rule.<br>- **moduleName**: module name of the caller. No matter what this field is set to, the correct module name will be sent to the peer.<br>- **ohos.dlp.params.sandbox**: available only for DLP files. | 21| entities | Array\<string> | No | Additional category information (such as browser and video player) of the target ability. It is a supplement to **action** in implicit Want and is used to filter ability types. | 22| moduleName<sup>9+</sup> | string | No | Module to which the ability belongs.| 23 24**Example** 25 26- Basic usage (called in a UIAbility object, where context in the example is the context object of the UIAbility). 27 28 ```ts 29 let want = { 30 'deviceId': '', // An empty deviceId indicates the local device. 31 'bundleName': 'com.extreme.test', 32 'abilityName': 'MainAbility', 33 'moduleName': 'entry' // moduleName is optional. 34 }; 35 this.context.startAbility(want, (error) => { 36 // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability. 37 console.log('error.code = ' + error.code) 38 }); 39 ``` 40 41- Passing a file descriptor (FD) (called in the UIAbility object, where context in the example is the context object of the UIAbility): 42 43 ```ts 44 import fs from '@ohos.file.fs'; 45 46 // ... 47 let fd; 48 try { 49 fd = fs.openSync('/data/storage/el2/base/haps/pic.png').fd; 50 } catch(e) { 51 console.log('openSync fail:' + JSON.stringify(e)); 52 } 53 let want = { 54 'deviceId': '', // An empty deviceId indicates the local device. 55 'bundleName': 'com.example.myapplication', 56 'abilityName': 'EntryAbility', 57 'moduleName': 'entry', // moduleName is optional. 58 'parameters': { 59 'keyFd':{'type':'FD', 'value':fd} 60 } 61 }; 62 this.context.startAbility(want, (error) => { 63 // Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability. 64 console.log('error.code = ' + error.code) 65 }); 66 // ... 67 ``` 68 69- For more details and examples, see [Want](../../application-models/application-model-composition.md). 70 71
