我创建了一个区块链实现，效果很好。然后，我想编写一个在删除消息时创建新链的程序。
而不是获得新的链，第二个块具有上一个链的最新块的数据，它丢弃了一个错误，我真的不明白这意味着什么。为什么是“ 1”？它甚至不是哈希，而是新链中块的索引。这是错误：
Uncaught TypeError: Cannot create property 'prevHash' on number '1'
at Chain.addBlock (chain.js:24)
at newChain (test.js:26)
at HTMLButtonElement.onclick (index.html:1)
有人可以解释为什么吗？我还附加了一个代码片段，以显示所有功能
// Chain.js
class Block {
constructor(id, data, prevHash = ''){
this.id = id;
this.prevHash = this.prevHash;
this.hash = this.calcHash();
this.data = data;
}
calcHash() {
return CryptoJS.SHA512(this.id + JSON.stringify(this.data)).toString();
}
}
class Chain {
constructor(){
this.chain = [this.genesisBlock()];
}
genesisBlock(){
return new Block(0,'Chain started.');
}
getLastBlock(){
return this.chain[this.chain.length - 1];
}
addBlock(block){
block.prevHash = this.getLastBlock().hash;
block.hash = block.calcHash();
this.chain.push(block)
}
isValid(){
for(let i = 1; i < this.chain.length; i++){
let prev = this.chain[i-1], current = this.chain[i];
if(current.hash !== prev.prevHash || current.hash !== current.calcHash())
return false;
}return true;
}
}
// Msg.js
class Msg {
constructor(msg, date){
this.msg = msg;
const D = new Date();
this.date = [D.getHours(), D.getMinutes(), D.getSeconds()].join(' : ');
}
}
// Test.js
FROZENCHAINS = [];
CHAIN = new Chain();
i = 0;
msg = () => {
let text = $('input').val();
i++;
CHAIN.addBlock(new Block(i, text));
let msg = JSON.stringify(CHAIN.chain,null, 4);
$('#log').text(msg);
let thisMSG = new Msg(text);
$('section').append('<div class="notification is-primary"><span class="tag">' + thisMSG.msg + '</span>'
+ '<span class="tag">Created at: ' + thisMSG.date + '</span><button onclick="$(this).parent().hide() && newChain()" align=center class="delete is-large"></button></div>')
}
newChain = () => {
FROZENCHAINS.push(CHAIN);
delete CHAIN;
CHAIN = new Chain();
CHAIN.addBlock(1,'Hi')
}.input {
margin: 10px 0;
}
.tag {
font-size: 23px !important;
background-color: whitesmoke !important;
margin: 5px;
}<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bulma/0.7.1/css/bulma.min.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.9-1/crypto-js.min.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.min.js" charset="utf-8"></script>
<title>Blockchain Chat</title>
</head>
<body>
<div class="tile is-parent">
<article class="tile is-child notification">
<p class="title">Blockchain Chat Part 1</p>
<div class="content">
<pre class="hero-body" id=log></pre>
<section class="hero-body"></section>
<input class="input" value="Hello World"/>
<button onclick="msg()" class="button">Send Message</button>
</div>
</body>
</html>最佳答案
您的addBlock函数需要一个Block，但是在newChain（）中提供1。将行更改为
CHAIN.addBlock(new Block(1,'Hi'));
关于javascript - 推送新区块时无法获得区块的先前哈希，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/52101106/