const SerialPort = require('serialport')
const Readline = require('@serialport/parser-readline')
const port = new SerialPort('/dev/ttyUSB2')
const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms))
const parser = port.pipe(new Readline({ delimiter: '\r\n' }))
parser.on('data', (data) => {
    if (data.includes('+CSQ:')) {
        try {
            const str = data.substring(data.indexOf(':') + 2)
            const list = str.split(',')
            // 分3等份正常信号值10~31
            const s = +list[0]
            if (s >= 10 && s <= 31) {
                if (s <= 17) {
                    console.log('信号差', 1, s);
                } else if (s > 17 && s <= 24) {
                    console.log('信号弱', 2, s);
                } else {
                    console.log('信号强', 3, s);
                }
            } else {
                console.log('信号差', 1);
            }
        } catch (error) {
            console.log(error);
        }
    }
})
port.write(Buffer.from('AT+CSQ\r\n'))
test()
async function test() {
    await sleep(5000)
    port.write(Buffer.from('AT+CSQ\r\n'))
    await test()
}