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                ### Interaction

<script src=""></script>
<script src=""></script>


    <input id="demo" type="button" value="Fill with dummy XDR"></input>

    <textarea id="xdr" rows="5" placeholder="Paste XDR here"></textarea>
    <input id="sign" type="button" disabled></input>
    <textarea id="signed" rows="5" placeholder="Signed XDR" disabled></textarea>


### Description

This pen makes use of `@cosmic-plus/ledger-wallet` and `stellar-sdk` to sign an XDR-encoded Stellar transaction with a Ledger Wallet. 

### Keypoints

- `ledgerWallet.sign()` takes a _StellarSdk.Transaction_ and returns a _Promise_.
- In case of success, the _Promise_ resolves to the signed _Transaction_.
- In case of error, the promise rejects an _Error_.
- In production, you'll want to check if the Ledger Wallet account is a legit signer for the transaction (e.g: using cosmic-lib).

### Challenges

- `[easy]` Add a selector that let us choose which account (number) to sign with.
- `[hard]` Implement a safety that throws an error when the Ledger Wallet account is not a legit signer for the transaction.

_Give it a try by forking that pen & editing the code!_

### Documentation

- [@cosmic-plus/ledger-wallet documentation](
- [js-stellar-sdk Transaction object](
- <a target="blank" href="">Transaction lifecycle</a>
- [cosmic-lib SignersUtils](

### Social

- [Discuss that pen on GalacticTalk](




                // $ npm install stellar-sdk @cosmic-plus/ledger-wallet
// const StellarSdk = require("stellar-sdk")
// const ledgerWallet = require("@cosmic-plus/ledger-wallet")
const $ = document.querySelector.bind(document)

const network = StellarSdk.Networks.TESTNET

/* Library */

function listen () {

function refresh () {
  $("#signed").value = null
  $("#signed").placeholder = "Signed XDR"

  if ($("#xdr").value) {
    if (ledgerWallet.publicKey) {
      setAction("Sign transaction", "enabled")
    } else {
      setAction("Waiting for Ledger Wallet...")
  } else {
    setAction("Waiting for a transaction...")

function signTx () {
  try {
    const xdr = $("#xdr").value
    const tx = new StellarSdk.Transaction(xdr, network)
    ledgerWallet.sign(tx).then(txSigned => {
      $("#signed").value = txSigned.toXDR()
  } catch (error) {
    setError("Invalid XDR")

function setAction (value, enabledFlag) {
  $("#sign").value = value
  $("#sign").disabled = !enabledFlag

function setError (message) {
  $("#signed").placeholder = message

function setXdr (xdr) {
  $("#xdr").value = xdr

/* Events */

ledgerWallet.onConnect = refresh
ledgerWallet.onDisconnect = listen

$("#demo").onclick = () => setXdr(dummy_xdr)
$("#xdr").oninput = refresh
$("#sign").onclick = signTx

$("body").onload = listen