# 定时器

# setTimeout(callback, delay, rest)

HarmonyOS Next 支持

Set a timer. Execute the registered callback function after the timer timeout

Parameter Description

Parameter	Type	Required	Instruction
callback	Function	Yes	Callback function
delay	Number	No	Delayed time, after which the function call will occur, in ms
rest	Any	No	param1, param2, ..., paramN and other additional parameters will be passed to the callback function as parameters

Return value

Return value	Type	Instruction
timeoutID	Number	The number of the timer, which can be passed to clearTimeout to cancel the timing

# clearTimeout(timeoutID)

HarmonyOS Next 支持

Cancel the timer set by setTimeout.

Parameter Description

Parameter	Type	Required	Instruction
timeoutID	Number	Yes	ID of the timer to cancel

# 最佳实践

定时器应当在组件、页面销毁时候取消，否则该定时器将成为游离定时器，无法被回收销毁。

<script lang="ts">
	let timer: ReturnType<typeof setTimeout> | null = null;
	export default {
		data() {
			return {};
		},
		methods: {
			onSetTimeout() {
				timer = setTimeout(() => {
					console.log("setTimeout");
				}, 1000);
			},
			clearTimer() {
				// clearTime
				if (timer) {
					clearTimeout(timer);
					timer = null;
				}
			},
		},
		beforeUnmount() {
			// clearTime
			this.clearTimer();
		},
	};
</script>

# setInterval(callback, delay, rest)

HarmonyOS Next 支持

Set a timer. Executes the registered callback function at the specified period (in ms)

Parameter Description

Parameter	Type	Required	Instruction
callback	Function	Yes	Callback function
delay	Number	No	Time interval between executing the callback function, in ms
rest	Any	No	param1, param2, ..., paramN and other additional parameters will be passed to the callback function as parameters

Return value

Return value	Type	Instruction
intervalID	Number	The number of the timer, which can be passed to clearInterval to cancel the timing

代码示例

this.timer = setInterval(() => {
	//TODO
}, 1000);

# clearInterval(intervalID)

HarmonyOS Next 支持

Cancel the timer set by setInterval.

Parameter Description

Parameter	Type	Required	Instruction
intervalID	Number	Yes	ID of the timer to cancel

# 最佳实践

<script lang="ts">
	let timer: ReturnType<typeof setTimeout> | null = null;
	export default {
		data() {
			return {};
		},
		methods: {
			onSetTimeout() {
				timer = setInterval(() => {
					console.log("setInterval");
				}, 1000);
			},
			clearTimer() {
				// clearTime
				if (timer) {
					clearInterval(timer);
					timer = null;
				}
			},
		},
		beforeUnmount() {
			// clearTime
			this.clearTimer();
		},
	};
</script>