如何更新类中的对象答案

【问题标题】：How to update an object in a class如何更新类中的对象
【发布时间】：2021-05-15 11:08:36
【问题描述】：

我已经在 nodejs 中构建了一个简单的 BlockChain。在钱包类中，我可以减去余额，但不能添加。这是 Wallet 类：

class Wallet {
    constructor(){
        const keyPair = crypto.generateKeyPairSync('rsa',{
            modulusLength: 2048,
            publicKeyEncoding: {type: 'spki', format: 'pem'},
            privateKeyEncoding: {type: 'pkcs8', format: 'pem'}
        });
        this.privateKey = keyPair.privateKey;
        this.publicKey = {key: keyPair.publicKey, balance: 0}
    }
    sendMoney(amount,receiverPublicKey,senderPrivateKey){
        const transaction = new Transaction(this.publicKey.key,receiverPublicKey,amount);

        const sign = crypto.createSign("SHA256");
        sign.update(transaction.toString()).end();

        const signature = sign.sign(this.privateKey);
        Bitcoin.addBlock(transaction,this.publicKey.key,signature);
       if(senderPrivateKey === this.privateKey && receiverPublicKey !== this.publicKey.key){
           this.publicKey.balance -= amount;
       }else if(receiverPublicKey === this.publicKey.key && senderPrivateKey !== this.privateKey){
           this.publicKey.balance += amount;
       }
    }
}

这是我发起交易的方式：

const satoshi = new Wallet();
const bob = new Wallet();

satoshi.publicKey.balance = 500;

satoshi.sendMoney(400,bob.publicKey.key,satoshi.privateKey);

我怎样才能将金额添加到余额中？

【问题讨论】：

标签： javascript node.js blockchain bitcoin cryptocurrency

【解决方案1】：

当您拨打satoshi.sendMoney() 时，“this”将指的是 satoshi 的钱包。这意味着，通过执行this.publicKey.balance += amount;，您正在尝试更新 satoshi 的余额，而不是 bob 的。您可以改用receiverPublicKey 来增加接收者的余额。

下面的示例更新了两个钱包。它仍然可能是错误的，因为我删除了一些检查，但我希望它有所帮助。

sendMoney(amount, receiverPublicKey, senderPrivateKey) {
    const transaction = new Transaction(this.publicKey.key,receiverPublicKey.key,amount);
    const sign = crypto.createSign("SHA256");
    sign.update(transaction.toString()).end();
    const signature = sign.sign(this.privateKey);
    Bitcoin.addBlock(transaction,this.publicKey.key,signature);

    if (senderPrivateKey === this.privateKey && receiverPublicKey.key !== this.publicKey.key) {
        this.publicKey.balance -= amount;
        receiverPublicKey.balance += amount;
    }
}

console.log(satoshi.publicKey.balance) // 500
console.log(bob.publicKey.balance)     // 0

satoshi.sendMoney(400, bob.publicKey/*.key*/, satoshi.privateKey);

console.log(satoshi.publicKey.balance) // 100
console.log(bob.publicKey.balance)     // 400

【讨论】：