# Timing and Time - [Introduction](#section11660541593) - [Directory Structure](#section161941989596) - [Usage](#section38521239153117) - [Available JS APIs](#section11908203714422) - [Sample Code](#section9938411124317) - [Repositories Involved](#section1371113476307) ## Introduction The timing and time module provides APIs for managing the system time. **Figure 1** Subsystem architecture ![](figures/subsystem_architecture.png "subsystem-architecture") ## Directory Structure ``` /base/miscservices/time ├── etc # Process configuration files ├── figures # Architecture diagram ├── interfaces # APIs for external systems and applications │ └── innerkits # APIs between services │ └── kits # APIs ├── profile # System service configuration files └── services # Service implementation ``` ## Usage ### Available JS APIs **Table 1** Major functions of systemTime

Interface name

describe

function setTime(time : number) : Promise<boolean>

Set the system time (1970-01-01 to the present in milliseconds), Promise method

function setTime(time : number, callback : AsyncCallback<boolean>) : void

Set the system time (1970-01-01 to the present in milliseconds), callback mode

function setDate(date: Date, callback: AsyncCallback<boolean>): void;

Set the system time (Date format), Promise method

function setDate(date: Date): Promise<boolean>

Set system time (Date format), callback method

function setTimezone(timezone: string, callback: AsyncCallback<boolean>): void

Set the system time zone, callback method

function setTimezone(timezone: string): Promise<boolean>

Set the system time zone, Promise method
**表 2** Major functions of systemTimer

Interface name

describe

function createTimer(options: TimerOptions, callback: AsyncCallback<number>): void

Create timer, callback method

function createTimer(options: TimerOptions): Promise<number>

Create timer, promise method

function startTimer(timer: number, triggerTime: number, callback: AsyncCallback<boolean>): void

Start the timer, callback mode

function startTimer(timer: number, triggerTime: number): Promise<boolean>

Start the timer, promise mode

function stopTimer(timer: number, callback: AsyncCallback<boolean>): void

Stop the timer, callback mode

function stopTimer(timer: number): Promise<boolean>

Stop the timer, promise mode

function destroyTimer(timer: number, callback: AsyncCallback<boolean>): void

Destroy the timer, callback method

function destroyTimer(timer: number): Promise<boolean>

Destroy the timer, the promise method
**表 3** parameter TimerOptions description of systemTimer

name

type

illustrate

type

number

TIMER_TYPE_REALTIME: Set as the system startup time timer, otherwise it is the walltime timer; TIMER_TYPE_WAKEUP: Set to wake-up timer, otherwise it is non-wake-up; const TIMER_TYPE_EXACT: Set as a precision timer, otherwise it is a non-precision timer; const TIMER_TYPE_IDLE: Set to IDLE mode timer, otherwise it is non-IDLE mode timer (not supported yet)

repeat

boolean

true Is a cyclic timer, false is a single timer

interval

number

If it is a cyclic timer, the repeat value should be greater than 5000 milliseconds, and the non-repeated timer is set to 0

wantAgent

wantAgent

Set the wantagent to notify, and notify when the timer expires

callback

=> void

Set the callback function, which will be triggered after the timer expires
### Sample Code Example fo using systemTime ``` // Import the module. import systemTime from '@ohos.systemTime'; // Set the system time asynchronously with a Promise. var time = 1611081385000; systemTime.setTime(time) .then((value) => { console.log(`success to systemTime.setTime: ${value}`); }).catch((err) => { console.error(`failed to systemTime.setTime because ${err.message}`) }); // Set the system time asynchronously with a callback. var time = 1611081385000; systemTime.setTime(time, (err, value) => { if (err) { console.error(`failed to systemTime.setTime because ${err.message}`); return; } console.log(`success to systemTime.setTime: ${value}`); }); ``` Example fo using systemTimer // Import the module import systemTimer from '@ohos.systemTimer'; console.log("start") var options:TimerOptions{ type:TIMER_TYPE_REALTIME, repeat:false, interval:Number.MAX_VALUE/2, persistent:false } console.log("create timer") let timerId = systemTimer.Timer(options) console.log("start timer") let startTimerRes = systemTimer.startTimer(timerId, 100000) console.log("stop timer") let stopTimerRes = systemTimer.stopTimer(timerId) console.log("destroy timer") let destroyTimerRes = systemTimer.destroyTimer(timerId) console.log('end'); ``` ## Repositories Involved **Misc services subsystem** [miscservices\_time](https://gitee.com/openharmony/miscservices_time/tree/master/)