# Receiving events

If you want to receive events no matter whether you have sent a command or not, you need to observe them. For that call the observe function on the application's events property and handle the received events using the received function:

app.events.observe().
  received((event, cancel) => {
    // ...
  });

# Cancelling observation

To cancel observing events call the provided cancel function. Unfortunately, this only works once you have received an event.

If you want to cancel even before that, e.g. after a given amount of time, use the cancel function of the started function. It is called immediately once observing events was started:

app.events.observe().
  started(cancel => {
    // ...
  }).
  received((event, cancel) => {
    // ...
  });

# Handling errors

If an error happens you will probably want to handle it. For that add the failed function and provide a callback that receives the error:

app.events.observe().
  failed(err => {
    // ...
  }).
  received((event, cancel) => {
    // ...
  });

# Filtering events

From time to time you do not want to receive all events, but only a subset that matches some filter criteria. For that hand over a where clause to the observe function.

E.g., to only get issued events, run the following code:

app.events.observe({
  where: { name: 'issued' }
}).
  received((event, cancel) => {
    // ...
  });

# Using the chaining API

You can chain all the aforementioned functions. Although not technically necessary, it is highly recommended to put the failed function first to ensure that you don't forget it:

app.events.observe().
  failed(err => {
    // ...
  }).
  started(cancel => {
    // ...
  }).
  received((event, cancel) => {
    // ...
  });