js-apis-timer.md

# Timer

> **NOTE:** The initial APIs of this module are supported since API version 4. Newly added APIs will be marked with a superscript to indicate their earliest API version.

## Module to Import

None

## Required Permissions

None

## setTimeout

setTimeout(handler[,delay[, ...args]]): number

Sets a timer for the system to call a function after the timer goes off.

- Parameters

  

  | Name    | Type        | Mandatory | Description                                                  |
  | ------- | ----------- | --------- | ------------------------------------------------------------ |
  | handler | Function    | Yes       | Function to be called after the timer goes off.              |
  | delay   | number      | No        | Number of milliseconds delayed before the execution. If this parameter is left empty, the default value **0** is used, which means that the execution starts immediately or as soon as possible. |
  | ...args | Array\<any> | No        | Additional parameter to pass to the handler after the timer goes off. |

- Return Value

  

  | Type   | Description |
  | ------ | ----------- |
  | number | Timer ID.   |

- Example

  ```
  export default {    
    setTimeOut() {        
      var timeoutID = setTimeout(function() {            
        console.log('delay 1s');
      }, 1000);    
    }
  }
  ```

## clearTimeout

clearTimeout(timeoutID: number): void

Cancels the timer created via **setTimeout()**.

- Parameter

  

  | Name      | Type   | Mandatory | Description                                                  |
  | --------- | ------ | --------- | ------------------------------------------------------------ |
  | timeoutID | number | Yes       | ID of the timer to cancel, which is returned by **setTimeout()** |

- Example

  ```
  export default {    
    clearTimeOut() {        
      var timeoutID = setTimeout(function() {            
        console.log('do after 1s delay.');        
      }, 1000);        
      clearTimeout(timeoutID);    
    }
  }
  ```

## setInterval

setInterval(handler[, delay[, ...args]]): number

Sets a repeating timer for the system to repeatedly call a function at a fixed interval.

- Parameters

  

  | Name    | Type        | Mandatory | Description                                                  |
  | ------- | ----------- | --------- | ------------------------------------------------------------ |
  | handler | Function    | Yes       | Function to be called repeatedly                             |
  | delay   | number      | No        | Number of milliseconds delayed before the execution          |
  | ...args | Array\<any> | No        | Additional parameter to pass to the handler after the timer goes off |

- Return Value

  

  | Type   | Description               |
  | ------ | ------------------------- |
  | number | ID of the repeated timer. |

- Example

  ```
  export default {    
    setInterval() {        
      var intervalID = setInterval(function() {            
        console.log('do very 1s.');        
      }, 1000);    
    }
  }
  ```

## clearInterval

clearInterval(intervalID: number): void

Cancels the repeating timer set via **setInterval()**.

- Parameter

  

  | Name       | Type   | Mandatory | Description                                                  |
  | ---------- | ------ | --------- | ------------------------------------------------------------ |
  | intervalID | number | Yes       | ID of the repeating timer to cancel, which is returned by **setInterval()**. |

- Example

  ```
  export default {    
    clearInterval() {        
      var intervalID = setInterval(function() {
        console.log('do very 1s.');
      }, 1000);
      clearInterval(intervalID);
    }
  }
  ```