Notes¶

var targetAddress = "0x02F024e0882B310c6734703AB9066EdD3a10C6e0";

var privateKey = "0x0123456789012345678901234567890123456789012345678901234567890123";
var wallet = new ethers.Wallet(privateKey);

// Promises we are interested in
var balancePromise = provider.getBalance(wallet.address);
var gasPricePromise = provider.getGasPrice();
var transactionCountPromise = provider.getCode(wallet.address);

var allPromise = Promsie.all([
    gasPricePromise,
    balancePromise,
    transactionCountPromise
]);

var sendPromise = allPromises.then(function(results) {
     // This function is ONLY called once ALL promises are fulfilled

     var gasPrice = results[0];
     var balance = results[1];
     var transactionCount = results[2];

     // Sending a transaction to an externally owned account (EOA) is 21000 gas)
     var txFeeInWei = gasPrice.mul(21000);

     // This will send the maximum amount (our balance minus the fee)
     var value = balance.sub(txFeeInWei);

     var transaction = {
         to: targetAddress,
         gasPrice: gasPrice,
         nonce: transactionCount,

         // The amount to send
         value: value,

         // Prevent replay attacks across networks
         chainId: provider.chainId,
     };

     var signedTransaction = wallet.sign(transaction);

     // By returning a Promise, the sendPromise will resolve once the
     // transaction is sent
     return provider.sendTransaction(signedTransaction);
});

var minedPromise = sendPromise.then(function(transaction) {
    // This will be called once the transaction is sent

    // This promise will be resolve once the transaction has been mined.
    return provider.waitForTransaction(transaction.hash);
});

minedPromise.then(function(transaction) {
    console.log("The transaction was mined: Block " + transaction.blockNumber);
});


// Promises can be re-used for their value; it will not make the external
// call again, and will provide the exact same result every time.
balancePromise.then(function(balance) {
    // This *may* return before teh above allPromises, since it only
    // required one external call. Keep in mind asynchronous calls can
    // be called out of order.
    console.log(balance);
});