it('provides a way to register a listener that is invoked once', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
emitter.once('type1', callback);
emitter.emit('type1', 'data');
emitter.emit('type1', 'data');
expect(callback.mock.calls.length).toBe(1);
expect(callback.mock.calls[0][0]).toBe('data');
});
'the midst of an emitting cycle', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
emitter.addListener('type1', callback);
callback.mockImplementation(function(data) {
emitter.removeCurrentListener();
});
emitter.emit('type1', 'data');
emitter.emit('type1', 'data');
expect(callback.mock.calls.length).toBe(1);
expect(callback.mock.calls[0][0]).toBe('data');
});
it('does not notify events of different types', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
emitter.addListener('type1', callback);
emitter.emit('type2');
expect(callback.mock.calls.length).toBe(0);
});
'registered for', function () {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
emitter.addListener('type1', callback);
emitter.emit('type1', 'data');
expect(callback.mock.calls[0][0]).toBe('data');
});
it('does not notify the listener of events after it is removed', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
var subscription = emitter.addListener('type1', callback);
subscription.remove();
emitter.emit('type1');
expect(callback.mock.calls.length).toBe(0);
});
it('does not notify of events after all listeners are removed', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
emitter.addListener('type1', callback);
emitter.removeAllListeners();
emitter.emit('type1');
expect(callback.mock.calls.length).toBe(0);
});
'been removed', function() {
var emitter = new BaseEventEmitter();
var callback = jest.genMockFunction();
var subscription = emitter.addListener('type1', function() {});
emitter.addListener('type1', callback);
subscription.remove();
emitter.emit('type1', 'data');
expect(callback.mock.calls[0][0]).toBe('data');
});
'emitted, even if more were added', function() {
var emitter = new BaseEventEmitter();
var callback1 = jest.genMockFunction();
var callback2 = jest.genMockFunction();
callback1.mockImplementation(function() {
emitter.addListener('type1', callback2);
});
emitter.addListener('type1', callback1);
emitter.emit('type1');
expect(callback1.mock.calls.length).toBe(1);
expect(callback2.mock.calls.length).toBe(0);
});
it('allows for the passing of the context when handling events', function() {
var emitter = new BaseEventEmitter();
var calledContext;
var callback = jest.genMockFunction();
callback.mockImplementation(function() {
calledContext = this;
});
var context = {};
emitter.addListener('type1', callback, context);
emitter.emit('type1', 'data');
expect(calledContext).toBe(context);
expect(callback.mock.calls[0][0]).toBe('data');
});
'emitted but later removed during the event loop', function() {
var emitter = new BaseEventEmitter();
var callback1 = jest.genMockFunction();
var callback2 = jest.genMockFunction();
callback1.mockImplementation(function() {
subscription.remove();
});
emitter.addListener('type1', callback1);
var subscription = emitter.addListener('type1', callback2);
emitter.emit('type1');
expect(callback1.mock.calls.length).toBe(1);
expect(callback2.mock.calls.length).toBe(0);
});