Event-driven design in LLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an event handler function.

LLD

def handle_event(event):
    if event.type == [1]:
        process_event(event)

Drag options to blanks, or click blank then click option'

Aevent

Bclick

Chandler

Dprocess

Attempts:

3 left

💡 Hint

Common Mistakes

Using the event object itself instead of its type.

Using unrelated words like 'handler' or 'process'.

The event type to check is usually a string like 'click' representing the event name.

2fill in blank

medium

Complete the code to publish an event to the event bus.

LLD

event_bus.[1](event)

Drag options to blanks, or click blank then click option'

Apublish

Blisten

Csubscribe

Dhandle

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'subscribe' which is for listening, not sending.

Using 'handle' which is for processing events.

Publishing an event means sending it to the event bus, so the method is usually called 'publish'.

3fill in blank

hard

Fix the error in the event subscription code.

LLD

event_bus.[1](event_type, callback_function)

Drag options to blanks, or click blank then click option'

Ahandle

Bpublish

Csubscribe

Demit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'publish' instead of 'subscribe'.

Using 'emit' which is similar to publish but not for subscription.

To listen for events, you subscribe to the event bus with the event type and callback.

4fill in blank

hard

Fill both blanks to create an event-driven loop that waits and processes events.

LLD

while True:
    event = event_queue.[1]()
    if event is not None:
        [2](event)

Drag options to blanks, or click blank then click option'

Aget_event

Bprocess_event

Cpublish

Dsubscribe

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'publish' or 'subscribe' in the loop incorrectly.

Not calling the processing function on the event.

The loop gets an event from the queue using 'get_event' and processes it with 'process_event'.

5fill in blank

hard

Fill all three blanks to define an event handler that filters and processes only 'update' events.

LLD

def event_handler(event):
    if event.type == [1]:
        data = event.[2]
        [3](data)

Drag options to blanks, or click blank then click option'

A'update'

Bpayload

Cprocess_update

Dtype

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'type' as a string instead of the attribute name.

Calling the wrong processing function.

The handler checks if the event type is 'update', extracts the 'payload', and calls 'process_update' with the data.