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Listeners

Here is the angular stone of Webserial, the listeners. With them, you can listen to the events that the device emits.

How to listen to an event​

When you create a new instance of the Relay class, you can listen to the events that the device emits.

machine.on('serial:message', (data) => {
    console.log(data);
});

Each event has a different data structure, so you need to check the data structure for each event.

Note

All events will return SerialEvent as shown in the image below.

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Get all available listeners​

For boardroid class there events that you can listen to, of course only listen to the events that you need.

Object​

To get all the available listeners, you can use the availableListeners property.

console.log(machine.availableListeners);

The result will be an object with the available listeners, and if you are listen each event

[
  {
    "type": "serial:connected",
    "listening": true
  },
  {
    "type": "serial:connecting",
    "listening": false
  },
  {
    "type": "serial:disconnected",
    "listening": true
  },
  {
    "type": "serial:error",
    "listening": true
  },
  {
    "type": "serial:lost",
    "listening": false
  },
  {
    "type": "serial:message",
    "listening": true
  },
  {
    "type": "serial:need-permission",
    "listening": true
  },
  {
    "type": "serial:reconnect",
    "listening": false
  },
  {
    "type": "serial:sent",
    "listening": false
  },
  {
    "type": "serial:soft-reload",
    "listening": true
  },
  {
    "type": "serial:timeout",
    "listening": false
  },
  {
    "type": "serial:unsupported",
    "listening": true
  }
]

Array​

But sometimes you don't want the object you want only an array with the available listeners, you can do this:

machine.availableListeners.map(el => el.type)

And one more time here is the result

[
  "serial:connected",
  "serial:connecting",
  "serial:disconnected",
  "serial:error",
  "serial:lost",
  "serial:message",
  "serial:need-permission",
  "serial:reconnect",
  "serial:sent",
  "serial:soft-reload",
  "serial:timeout",
  "serial:unsupported"
]

Serial connected​

When the serial is connected, this event is dispatched.

machine.on('serial:connected', event => {
    console.log(event.detail);
});

Serial connecting​

When the serial is trying to connect, this event is dispatched.

machine.on('serial:connecting', event => {
    // without data
});

Serial disconnected​

When the serial is disconnected, this event is dispatched.

machine.on('serial:disconnected', event => {
    console.log(event.detail);
});

Serial error​

When the serial has an error, this event is dispatched.

machine.on('serial:error', event => {
    console.log(event.detail);
});

Serial lost​

When the serial is lost, this event is dispatched.

machine.on('serial:lost', event => {
    console.log(event.detail);
});

Serial message​

When the serial receives a message, this event is dispatched.

Note

This event is dispatched along others events that send event of machine, so this event is only for debug.

machine.on('serial:message', event => {
    console.log(event.detail);
});

Serial need permission​

When the serial needs permission, this event is dispatched. This occurs because user interaction is needed to request the serial.

Recommendation: Use a button or a screen to show what is happening.

machine.on('serial:need-permission', event => {
    console.log(event.detail);
});

Serial reconnect​

When the serial is trying to reconnect, this event is dispatched.

machine.on('serial:reconnect', event => {
    // without data
});

Serial sent​

When the serial sends a message to machine, this event is dispatched.

Note

This event is more oriented for debug.

machine.on('serial:sent', event => {
    console.log(event.detail);
});
structure event.detail
{
  "event": "string",
  "bytes": []
}

Serial soft reload​

When the serial is trying to soft reload, this event is dispatched.

machine.on('serial:soft-reload', event => {
    // without data
});

Serial timeout​

When the serial has a timeout, this event is dispatched.

machine.on('serial:timeout', event => {
    console.log(event.detail);
});

Serial unsupported​

When the serial is unsupported, this event is dispatched.

machine.on('serial:unsupported', event => {
    console.log(event.detail);
});