Understanding the Adapter Pattern
Adapt incompatible APIs and services to a consistent interface without requiring the rewriting of client logic.
We'll cover the following...
Why this pattern matters
In Node.js backends, we often work with inconsistent APIs.
One HTTP client returns
{ data, status }, another just returns the raw body.A legacy module uses callbacks, but the rest of our code is
async/await.We integrate Stripe, PayPal, and a custom billing service—each with its own quirks.
Without a plan, we end up scattering if/else conditions and conversion logic everywhere—converting payloads, renaming fields, reshaping responses. This results in fragile, duplicated code that is tightly coupled to third-party or legacy libraries.
This is exactly where the Adapter Pattern helps. It provides a consistent interface over inconsistent dependencies, keeping our core logic clean, testable, and easy to replace.
How the pattern works
At its core, an adapter acts as a translator between two systems:
The client expects a certain interface.
The adaptee (external or legacy module) exposes a different one.
The adapter wraps the original component (the adaptee) and exposes the interface the client needs, translating inputs and outputs as it goes.
The client talks to the adapter in its own language. The adapter then translates and delegates the request to the underlying ...