Hardcoding a private key is a significant security risk. Even if it's a default key for development, it should not be committed to the repository. This key should be generated and stored securely, or at least be configurable and not a hardcoded constant in the source code. Please remove this and implement a secure way to handle the private key.

This file contains multiple merge conflict markers (<<<<<<<, =======, >>>>>>>). These must be resolved before the pull request can be merged. Please rebase your branch on top of the target branch or resolve the conflicts manually.

This file contains merge conflict markers. This indicates an unresolved merge conflict. Please resolve the conflicts, for example by running yarn install after resolving conflicts in package.json, and commit the updated yarn.lock file.

There is a typo in the property name desination. It should be destination. This will likely cause the 'withdraw' RPC call to fail.

There are a couple of issues in the getRoutes method that could lead to a crash:

1. On line 299, urlParams && urlParams[1] can be undefined, which results in Number(undefined), which is NaN. This will likely cause issues in the getroute RPC call.
2. On line 307, res.route[0] is accessed without checking if res.route is empty. If the RPC call returns no routes, this will cause a crash.

Please add defensive checks to handle these cases gracefully.

    getRoutes = async (urlParams?: Array<string>) => {
        const msatoshi = Number(urlParams?.[1] || 0) * 1000;
        const id = urlParams?.[0];

        if (!id || !msatoshi) {
            return { routes: [] };
        }

        const res = await this.rpc('getroute', {
            id,
            msatoshi,
            riskfactor: 2
        });

        const route = res.route?.[0];

        if (!route || route.length === 0) {
            return { routes: [] };
        }

        return {
            routes: [
                {
                    total_fees: (route[0].msatoshi - msatoshi) / 1000
                }
            ]
        };
    };

Using Math.random() for generating a unique label is not guaranteed to be unique and can lead to collisions, especially if invoices are created in quick succession. Consider using a more robust method for generating unique IDs, such as a timestamp combined with random characters, or a library like uuid.

The methods decodePaymentRequest and getNodeInfo have unsafe access to urlParams. If urlParams is undefined or empty, [urlParams && urlParams[0]] becomes [undefined], which is likely not the intended behavior and could cause RPC errors. It's better to avoid passing any arguments if urlParams[0] is not available.

nit: lock the version

@a-khushal , Can we add an isConnected method as well?