Using the Custom Module in Wallet API Client

The Custom Module allows you to interact with any Custom Handler supported by the server.

Custom Module Overview

ℹ️

We are still working on improving the type safety of custom modules

Step 1

First, you need a Custom Module, you can import one from another lib or create it.

To create a Custom Module, you need to import and extend the CustomModule class.

You can add any method you want in your class and do any logic you need to.
Use this.request<ParamType, ReturnType>("custom.handler", param) to call the Custom Handler methods supported by the server.

import { CustomModule } from "@ledgerhq/wallet-api-client";
 
type CustomLogHandlersType = {
  "custom.log": (message: string) => Promise<{ res: "hello" }>;
};
 
class CustomLog extends CustomModule {
  log(message: string) {
    return this.request<
      Parameters<CustomLogHandlersType["custom.log"]>[0],
      ReturnType<CustomLogHandlersType["custom.log"]>
    >("custom.log", message);
  }
}

Step 2

Go back to your transport declaration from your Wallet API Configuration.

You need to adapt the WalletAPIClient by passing a function that returns your custom handler.

ℹ️

You can use the defaultLogger export from the @ledgerhq/wallet-api-client if you weren't using the second parameter of the WalletAPIClient

import { WalletAPIClient, defaultLogger } from "@ledgerhq/wallet-api-client";
 
const walletApiClient = new WalletAPIClient(
  transport,
  defaultLogger,
  (client) => {
    return new CustomLog(client);
  }
);

ℹ️

You can also use multiple Custom Module in an object.

import { WalletAPIClient, defaultLogger } from "@ledgerhq/wallet-api-client";
 
const walletApiClient = new WalletAPIClient(
  transport,
  defaultLogger,
  (client) => {
    return {
      log: new CustomLog(client),
      log2: new CustomLog2(client),
      device: new CustomDevice(client),
    };
  }
);

Step 3

Access the Custom Module via walletApiClient.custom.

// Example using one module
const res = await walletApiClient.custom.log("test");
// Example using multiple modules
const res2 = await walletApiClient.custom.log.log("test");

Handling Errors

Make sure to handle errors gracefully and provide appropriate feedback to the user.
Additionally, always remember to disconnect the WindowMessageTransport when you're done interacting with the Ledger Wallet API to free up resources.

Currency Device