callbag-mock

Callbag mock with manual emitting and signal tapping.

Useful for unit testing other callbag packages, or for triggering signals in callbag chains from non-callbag code.

npm install callbag-mock

usage

(isSource?: boolean, reporter?: function) => mock

The isSource boolean decides whether the mock will handshake back when initialised (meaning it is a source).

A reporter, if provided, will be called each time the mock receives a signal:

(t: 0 | 1 | 2, d: any, in: 'body' | 'talkback') => void

The third in parameter tells you whether the signal was received in the function body or the talkback.

The mock instance has an .emit(t,d) method for manually triggering signals:

(t: 0 | 1 | 2, d: any)

There is a .getReceivedData() method to get all received data so far.

Use .getMessages() if you want all messages as [t, d] tuples.

Get references to sent talkbacks through .getTalkback() and received talkbacks through .getPartnerTalkback().

You can also .checkConnection() to see whether or not the callbag has a live connection.

example

const mock = require('callbag-mock');
 
const reporter = (name, dir, t, d) => {
  if (t !== 0) console.log(name, dir, t, d);
}
 
const source = mock('source', reporter, true);
const sink = mock('sink', reporter);
 
source.checkConnection(); // false
sink.checkConnection(); // false
 
source(0, sink);
 
source.getTalkback() === sink.getPartnerTalkback() // true
sink === source.getPartnerTalkback() // true
 
source.emit(1, 'foo'); // 'sink', 'body', 1, 'foo'
sink.emit(1, 'bar'); // 'source', 'talkback', 1, 'bar'
 
sink.getReceivedData(); // ['foo']
 
source.checkConnection(); // true
sink.checkConnection(); // true