Architecture

The Fedimint Web SDK Core Web library is a modular and extensible JavaScript library designed to interact with the Fedimint client in a web browser. It provides a high-level API for developers to manage federated e-cash wallets, perform operations like minting and spending e-cash, and interact with the Lightning Network. The library is structured to promote maintainability, scalability, and ease of use, leveraging modern software development practices.

The Core Web library is built around a set of composable services and a communication layer that interacts with a Web Worker running WebAssembly (WASM) code.

FedimintWallet

The FedimintWallet class serves as the main entry point for the library. It orchestrates the various services and the WorkerClient.

Code

WorkerClient

The WorkerClient manages all communication between the main thread and the Web Worker.

• Initializes and maintains the Web Worker instance.
• Handles message passing and response callbacks.
• Provides methods for sending RPC requests and handling streaming responses.

INFO

The WorkerClient should not be used directly by the end user. Instead, the FedimintWallet class should be used to interact with the library.

Code

Services

The library is decomposed into several services, each encapsulating a specific domain of functionality. This modular design allows for easier maintenance and testing.

FederationService

Handles federation-related operations such as joining federations, retrieving configurations, and obtaining invite codes.

MintService

Manages operations related to minting and handling e-cash notes, including redeeming, reissuing, spending, and validating notes.

LightningService

Facilitates interactions with the Lightning Network, handling invoice creation/payment, gateway management, and event subscriptions.

BalanceService

Manages balance inquiries and subscriptions, allowing users to fetch current wallet balance and subscribe to changes.

RecoveryService

Manages recovery operations, including checking for pending recoveries, waiting for completion, and subscribing to progress updates.

Utilities

The library includes a configurable logging utility to aid in development and debugging.

Logger Utility

A Logger class supports multiple log levels: DEBUG, INFO, WARN, ERROR, and NONE.

Users can set the desired log level using the setLogLevel method.