# HiAppEvent >![](../../public_sys-resources/icon-note.gif) **NOTE:** >The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version. ## Modules to Import ``` import hiAppEvent from '@ohos.hiAppEvent'; ``` ## System Capabilities SystemCapability.HiviewDFX.HiAppEvent ## hiAppEvent.write write$eventName: string, eventType: EventType, keyValues: object, callback: AsyncCallback$: void Writes event information to the event file of the current day. This function supports JSON parameters and uses an asynchronous callback to return the result. - Parameters

Name	Type	Mandatory	Description
eventName	string	Yes	Indicates the application event name.
eventType	EventType	Yes	Indicates the application event type.
keyValues	object	Yes	Indicates an array of JSON parameters of the application event. A key must be a string, and a value must be a string, number, boolean, or Array (which can only be a string, number, or boolean).
callback	AsyncCallback<void>	No	Indicates the callback function, which can be used to process the received return value. Value 0 indicates that the event verification is successful, and the event will be written to the event file asynchronously. A value greater than 0 indicates that invalid parameters are present in the event, and the event will be written to the event file asynchronously after the invalid parameters are ignored. A value smaller than 0 indicates that the event verification fails, and the event will not be written to the event file.

- Example ``` hiAppEvent.write("test_event", hiAppEvent.EventType.FAULT, {"int_data":100, "str_data":"strValue"}, (err, value) => { if (err) { // Event writing exception: Write the event to the event file after the invalid parameters in the event are ignored, or stop writing the event if the event verification fails. console.error(`failed to write event because ${err.code}`); return; } // Event writing succeeded. console.log(`success to write event: ${value}`); }); ``` ## hiAppEvent.write write$eventName: string, eventType: EventType, keyValues: object$: Promise Writes event information to the event file of the current day. This function supports JSON parameters and uses a promise to return the result. - Parameters

Name	Type	Mandatory	Description
eventName	string	Yes	Indicates the application event name.
eventType	EventType	Yes	Indicates the application event type.
keyValues	object	Yes	Indicates an array of JSON parameters of the application event. A key must be a string, and a value must be a string, number, boolean, or Array (which can only be a string, number, or boolean).

- Return values

Type	Description
Promise<void>	Promise used to process the callback in the then() and catch() methods when event writing succeeded or failed.

- Example ``` hiAppEvent.write("test_event", hiAppEvent.EventType.FAULT, {"int_data":100, "str_data":"strValue"}) .then((value) => { // Event writing succeeded. console.log(`success to write event: ${value}`); }).catch((err) => { // Event writing exception: Write the event to the event file after the invalid parameters in the event are ignored, or stop writing the event if the event verification fails. console.error(`failed to write event because ${err.code}`); }); ``` ## hiAppEvent.configure configure$config: ConfigOption$: boolean Configures the application event logging function, such as setting the event logging switch and maximum size of the directory that stores the event logging files. - Parameters

Name	Type	Mandatory	Description
config	ConfigOption	Yes	Configuration items for application event logging.

- Return values

Type	Description
boolean	Returns true if the configuration is successful; returns false otherwise.

- Example ``` // Configure the application event logging switch. hiAppEvent.configure({ disable: true }); // Configure the maximum size of the directory that stores the event logging files. hiAppEvent.configure({ maxStorage: '100M' }); ``` ## ConfigOption Provides the configuration items for application event logging.

Name	Type	Mandatory	Description
disable	boolean	No	Application event logging switch. The value true means to disable the application event logging function, and the value false means the opposite.
maxStorage	string	No	Maximum size of the event file storage directory. The default value is 10M. If the specified size is exceeded, the oldest event logging files in the storage directory will be deleted to free up space.

## EventType Enumerates event types.

Name	Default Value	Description
FAULT	1	Fault event
STATISTIC	2	Statistical event
SECURITY	3	Security event
BEHAVIOR	4	Behavior event

## Event Provides constants that define the names of all predefined events.

Name	Parameter Type	Readable	Writable	Description
USER_LOGIN	string	Yes	No	User login event.
USER_LOGOUT	string	Yes	No	User logout event.
DISTRIBUTED_SERVICE_START	string	Yes	No	Distributed service startup event.

## Param Provides constants that define the names of all predefined event parameters.

Name	Parameter Type	Readable	Writable	Description
USER_ID	string	Yes	No	Custom user ID.
DISTRIBUTED_SERVICE_NAME	string	Yes	No	Distributed service name.
DISTRIBUTED_SERVICE_INSTANCE_ID	string	Yes	No	Distributed service instance ID.