What is middleware and event emitters?

Question

Accepted Answer

Middleware is software that acts as a bridge between different applications or systems. Event emitters are objects that emit events that can be listened to and acted upon.

Middleware is used to handle communication between different systems or applications.
It can modify or enhance the data being passed between systems.
Event emitters are objects in programming that emit events which can be listened to by other parts of the program.
They are commonly used in event-driven programming to handle asynchronous operations.
Examples of middleware include Express.js for Node.js applications, and Salesforce Commerce Cloud's OCAPI for integrating with external systems.
Examples of event emitters include Node.js's EventEmitter class.

Accepted Answer

Event emitters in Commerce Cloud typically refer to components or modules that generate and emit events based on specific triggers or actions within the system. These events could include customer actions such as placing an order, updating a profile, or subscribing to a newsletter, as well as system events like inventory updates, price changes, or payment processing.

Middleware often interacts with event emitters to handle and respond to these events appropriately. For example, middleware might listen for certain events emitted by the system, and then trigger additional actions such as sending notifications, updating databases, or invoking external services.

What is middleware and event emitters?

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