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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

              ### Interaction

<script src="https://cdn.cosmic.plus/stellar-sdk"></script>
<script src="https://cdn.cosmic.plus/ledger-wallet@1.x"></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](https://cosmic.plus/#view:js-ledger-wallet)
- [js-stellar-sdk Transaction object](https://stellar.github.io/js-stellar-sdk/Transaction.html)
- <a target="blank" href="https://www.stellar.org/developers/guides/concepts/transactions.html#transaction-lifecycle">Transaction lifecycle</a>
- [cosmic-lib SignersUtils](https://cosmic.plus/#view:js-cosmic-lib/web/doc/SignersUtils.html)

### Social

- [Discuss that pen on GalacticTalk](https://galactictalk.org/d/2091-pen-of-the-week-ledger-wallet-sign-transaction)
              // $ 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
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