如何使清除超时正常工作以取消(中断)设置超时循环?

Question

我正在使用Node.js来构建一个可以读取USB LoRa模块数据并控制Raspberry Pi GPIO引脚的应用程序。

有三个主要功能：

1. 将 GPIO 设置为打开(给定引脚 0 信号)

2. 将 GPIO 设置为关闭(给定引脚 1 信号)

3. 将 GPIO 设置为在一段时间后关闭(使用setTimeout功能)

主要功能运行良好。

问题是在setTimeout循环中，我想随时终止它。

我试图使用clearTimeout来取消setTimeout循环，但它似乎不起作用。我做错了什么吗？

例如。

在 LoRa 收到的数据包中使用字符串"TurnOn15s"。 我无法随时终止超时。我必须等到 15 秒结束才能关闭 GPIO 引脚。如果我在超时执行期间调用 deviceTurnOff(1) 函数， 我将在循环结束后得到两个输出。

程序输出如下：

// Output by `deviceTurnOn(0,15000)` from received LoRa packet.
Received:0, the solenoid valve has been opened!                                 
Received packet: !20!96 0 0 0 53 0 0 28 11 3 TurnOn15s RSSI: -40 SNR:   6
// Output by `setTimeout` function.
Received:1, the solenoid valve has been closed!                                 
// Output by deviceTurnOff(1) from received LoRa packet.
Received:1, the solenoid valve has been closed!                                 
Received packet: !18!96 0 0 0 53 0 0 29 9 3 TurnOff RSSI: -41 SNR:   7 

以下是部分代码：

var turnOffTimeout = null; // turnOffTimeout
// Control Raspberry Pi GPIO pins.
function deviceTurnOn(controlValueType, timeout) {
// Do Turn On Raspberry Pi GPIO pins.
if (timeout == -1) {
// if no time string in the packet.
console.log(`Received:${controlValueType}, the solenoid valve has been opened!`);
OutputDevice.writeSync(controlValueType);
} else {
// if contains time string in the packet.
console.log(`Received:${controlValueType}, the solenoid valve has been opened!`);
OutputDevice.writeSync(controlValueType);
turnOffTimer(timeout);
}
}
// Control Raspberry Pi GPIO pins.
function deviceTurnOff(controlValueType) {
// Do Turn Off Raspberry Pi GPIO pins.
console.log(`Received:${controlValueType}, the solenoid valve has been closed!`);
OutputDevice.writeSync(controlValueType);
// clearTimeout
if (turnOffTimeout) {
clearTimeout(turnOffTimeout);
}
}

// Raspberry Pi GPIO pins turn off timeout.
function turnOffTimer(timeout) {
turnOffTimeout = setTimeout(function() {
deviceTurnOff(1);
}, timeout);
}

包含三个功能：deviceTurnOn、deviceTurnOff、turnOffTimer

函数调用的格式为

deviceTurnOff(1);
deviceTurnOn(0,timeout);
// Timeout is milliseconds

更新;

我尝试按如下方式修改我的程序，我得到的输出与以前的版本代码相同，问题仍未解决。

var turnOffTimeout = null; // turnOffTimeout
// Control Raspberry Pi GPIO pins.
function deviceTurnOn(controlValueType, timeout) {
// Do Turn On Raspberry Pi GPIO pins.
if (timeout == -1) {
// if no time string in the packet.
console.log(`Received:${controlValueType}, the solenoid valve has been opened!`);
OutputDevice.writeSync(controlValueType);
}
else {
// if contains time string in the packet.
console.log(`Received:${controlValueType}, the solenoid valve has been opened!`);
OutputDevice.writeSync(controlValueType);
// clearTimeout.
clearTimeout(turnOffTimeout);
// set new timeout.
turnOffTimeout = setTimeout(function () {
deviceTurnOff(1);
}, timeout);
}
}
// Control Raspberry Pi GPIO pins.
function deviceTurnOff(controlValueType) {
// Do Turn Off Raspberry Pi GPIO pins.
console.log(`Received:${controlValueType}, the solenoid valve has been closed!`);
clearTimeout(turnOffTimeout);
OutputDevice.writeSync(controlValueType);
}

Answer 1

确保在启动和停止时清除超时，您也不需要检查是否设置了超时。 此外，实际上不需要第三个函数来取消计时器，因为clearTimeout已经存在：

var timeout;
var timeout_ms = 10000;
var stop = function(){
clearTimeout(timeout);
turnOff();
}
var start(){
clearTimeout(timeout); // clear existing t/o just in case
timeout = setTimeout(turnOff,timeout_ms);
turnOn();
}