# @ohos.application.Want (Want)
Want is a carrier for information transfer between objects (application components). Want can be used as a parameter of **startAbility()** 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.
> **NOTE**
>
> The APIs of this module are supported since API version 8 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.
## Modules to Import
```ts
import Want from '@ohos.application.Want';
```
## Attributes
**System capability**: SystemCapability.Ability.AbilityBase
| Name | Type | Mandatory| Description |
| ----------- | -------------------- | ---- | ------------------------------------------------------------ |
| deviceId | string | No | ID of the device running the ability. If this field is unspecified, the local device is used. |
| bundleName | string | No | Bundle name.|
| 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.|
| uri | string | No | URI information to match. If **uri** is specified in a **Want** object, the **Want** object will match the specified URI information, including **scheme**, **schemeSpecificPart**, **authority**, and **path**.|
| 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. |
| flags | number | No | How the **Want** object will be handled. By default, numbers are passed in. For details, see [flags](js-apis-ability-wantConstant.md#wantconstantflags).|
| action | string | No | Action to take, such as viewing and sharing application details. In implicit **Want**, you can define this attribute and use it together with **uri** or **parameters** to specify the operation to be performed on the data. For details, see [action](js-apis-ability-wantConstant.md#wantconstantaction). For details about the definition and matching rules of implicit Want, see [Matching Rules of Explicit Want and Implicit Want](../../application-models/explicit-implicit-want-mappings.md). |
| parameters | {[key: string]: any} | 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), 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. |
| entities | Array\<string> | No | Additional category information (such as browser and video player) of the ability. It is a supplement to the **action** field for implicit Want. and is used to filter ability types. For details, see [entity](js-apis-ability-wantConstant.md#wantconstantentity). |
**Example**
- Basic usage (called in a UIAbility object, where context in the example is the context object of the UIAbility).
```ts
import Want from '@ohos.application.Want';
import { BusinessError } from '@ohos.base';
import UIAbility from '@ohos.app.ability.UIAbility';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
let want: Want = {
'deviceId': '', // An empty deviceId indicates the local device.
'bundleName': 'com.example.myapplication',
'abilityName': 'EntryAbility',
};
class MyAbility extends UIAbility{
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam){
this.context.startAbility(want, (error: BusinessError) => {
// Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
console.error(`error.code = ${error.code}`);
});
}
}
```
- Data is transferred through user-defined fields. The following data types are supported (called in a UIAbility object, where context in the example is the context object of the UIAbility):
* String
```ts
import Want from '@ohos.application.Want';
let want: Want = {
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
keyForString: 'str',
},
};
```
* Number
```ts
import Want from '@ohos.application.Want';
let want: Want = {
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
keyForInt: 100,
keyForDouble: 99.99,
},
};
```
* Boolean
```ts
import Want from '@ohos.application.Want';
let want: Want = {
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
keyForBool: true,
},
};
```
* Object
```ts
import Want from '@ohos.application.Want';
let want: Want = {
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
keyForObject: {
keyForObjectString: 'str',
keyForObjectInt: -200,
keyForObjectDouble: 35.5,
keyForObjectBool: false,
},
},
};
```
* Array
```ts
import Want from '@ohos.application.Want';
let want: Want = {
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
keyForArrayString: ['str1', 'str2', 'str3'],
keyForArrayInt: [100, 200, 300, 400],
keyForArrayDouble: [0.1, 0.2],
keyForArrayObject: [{obj1: 'aaa'}, {obj2: 100}],
},
};
```
* File descriptor (FD)
```ts
import fs from '@ohos.file.fs';
import Want from '@ohos.application.Want';
import { BusinessError } from '@ohos.base';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import UIAbility from '@ohos.app.ability.UIAbility';
let fd: number = 0;
try {
fd = fs.openSync('/data/storage/el2/base/haps/pic.png').fd;
} catch(e) {
console.error(`openSync fail: ${JSON.stringify(e)}`);
}
let want: Want = {
deviceId: '', // An empty deviceId indicates the local device.
bundleName: 'com.example.myapplication',
abilityName: 'EntryAbility',
parameters: {
'keyFd':{'type':'FD', 'value':fd}
}
};
class MyAbility extends UIAbility{
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam){
this.context.startAbility(want, (error: BusinessError) => {
// Start an ability explicitly. The bundleName, abilityName, and moduleName parameters work together to uniquely identify an ability.
console.error(`error.code = ${error.code}`);
});
}
}
```
- For more details and examples, see [Want](../../application-models/want-overview.md).