update to newer version

wallet/transaction.js

@@ -0,0 +1,69 @@
+const ChainUtil = require('../chain-util');
+const { MINING_REWARD } = require('../config');
+
+class Transaction {
+  constructor() {
+    this.id = ChainUtil.id();
+    this.input = null;
+    this.outputs = [];
+  }
+
+  update(senderWallet, recipient, amount) {
+    const senderOutput = this.outputs.find(output => output.address === senderWallet.publicKey);
+
+    if (amount > senderOutput.amount) {
+      console.log(`Amount: ${amount} exceeds balance.`);
+      return;
+    }
+
+    senderOutput.amount = senderOutput.amount - amount;
+    this.outputs.push({ amount, address: recipient });
+    Transaction.signTransaction(this, senderWallet);
+
+    return this;
+  }
+
+  static transactionWithOutputs(senderWallet, outputs) {
+    const transaction = new this();
+    transaction.outputs.push(...outputs);
+    Transaction.signTransaction(transaction, senderWallet);
+    return transaction;
+  }
+
+  static newTransaction(senderWallet, recipient, amount) {
+    if (amount > senderWallet.balance) {
+      console.log(`Amount: ${amount} exceeds balance.`);
+      return;
+    }
+
+    return Transaction.transactionWithOutputs(senderWallet, [
+      { amount: senderWallet.balance - amount, address: senderWallet.publicKey },
+      { amount, address: recipient }
+    ]);
+  }
+
+  static rewardTransaction(minerWallet, blockchainWallet) {
+    return Transaction.transactionWithOutputs(blockchainWallet, [{
+      amount: MINING_REWARD, address: minerWallet.publicKey
+    }]);
+  }
+
+  static signTransaction(transaction, senderWallet) {
+    transaction.input = {
+      timestamp: Date.now(),
+      amount: senderWallet.balance,
+      address: senderWallet.publicKey,
+      signature: senderWallet.sign(ChainUtil.hash(transaction.outputs))
+    }
+  }
+
+  static verifyTransaction(transaction) {
+    return ChainUtil.verifySignature(
+      transaction.input.address,
+      transaction.input.signature,
+      ChainUtil.hash(transaction.outputs)
+    );
+  }
+}
+
+module.exports = Transaction;