The Essential Role of the Trampoline Technique in Reactive Programming Libraries

The Essential Role of the Trampoline Technique in Reactive Programming Libraries



Sep 28, 2023


Reactive programming is a popular paradigm that deals with asynchronous data streams and allows developers to build efficient and responsive applications. Creating a library for reactive programming is essential for effectively managing and delivering events to multiple subscribers. In this article, we will discuss the challenges faced in delivering events in reactive programming and how the trampoline technique can resolve these issues.

Reactive Programming and Event Delivery

However, this approach can lead to issues when a closure requests additional work to deliver a new event recursively. In such cases, other closures may receive the events in the wrong order. This problem arises because the delivery mechanism behaves like a stack algorithm, whereas it should be based on a queue.

Introducing the Trampoline Technique

The trampoline technique is an effective solution to this problem. It ensures that a new event is not delivered until all closures have received the current event. This technique modifies the event delivery mechanism to behave like a queue, allowing events to be processed in the correct order.

How Trampoline Technique Works

Instead of running closures in a loop, the trampoline technique maintains a queue of closures to be executed. When a new event is received, it is added to the queue. The trampoline mechanism ensures that each closure in the queue is executed before moving on to the next event.

When a closure requests additional work, the trampoline technique adds the new closure to the queue rather than executing it immediately. This approach prevents recursive calls and ensures that all closures receive events in the correct order.

Benefits of the Trampoline Technique

  1. Improved event order: By implementing the trampoline technique, the event delivery mechanism can maintain the correct order of events for all closures.

  2. Prevents stack overflow: Recursive calls can lead to stack overflow issues. The trampoline technique eliminates the risk of stack overflow by adding new closures to the queue instead of executing them recursively.

  3. Efficient event delivery: The trampoline technique allows for efficient event delivery, ensuring that all subscribers receive the events as they are generated, minimizing latency and improving overall performance.


The trampoline technique is a powerful solution for improving event delivery in reactive programming libraries. By ensuring that events are delivered in the correct order and preventing stack overflow issues, the trampoline technique enables developers to create efficient and responsive applications. When designing a library for reactive programming, it is crucial to consider the implementation of the trampoline technique for optimal event management and delivery.

Here is a one of the use cases

Verge’s EventEmitter is a core component in the Verge library for building reactive applications in Swift. It leverages the trampoline technique to manage event delivery efficiently. By employing the trampoline technique, EventEmitter guarantees that events are delivered in the correct order, preventing stack overflow issues and ensuring efficient event handling, even in high-load scenarios.