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Registers

The register client classe (Register<T>) allow to read, write and track changes of service registers.

Aside from the data type, there are 3 different type of access control on registers:

  • read only: the value can be read, but not written.
  • read write: the value can be read and written.
  • const: the value of the register is constant. It may change on the next reset but this is not a common scenario.

read​

The read method gets the current reported value stored in the register.

const sensor = new ds.Temperature()
setInterval(async () => {
    const t = await sensor.reading.read()
    console.log(t)
}, 1000)

write​

The write method sets the current value of the register and only applies to read-write registers.

const led = new ds.Led()

await led.intensity.write(0.5)

subscribe​

The subscribe method registers a callback that gets raised whenever a value update arrives.

const sensor = new ds.Temperature()
sensor.reading.subscribe(value => {
    console.log(value)
})

The subscribe method returns an unsubscribe function that allows to remove the callback.

const sensor = new ds.Temperature()
const unsubscribe = sensor.reading.subscribe(value => {
    console.log(value)
})

// later on
unsubscribe()