Last updated on May 24th, 2023
Cryptocurrencies and the blockchain technology that supports them have taken the world by storm, from their humble beginnings as an academic idea more than a decade ago to their increased use in many industries today.
Blockchain technology is getting a lot of attention because it can improve security in environments where you can’t trust anyone, force decentralization, and speed up processes.
Python has been the standard programming language for building blockchains for a long time. But as this incredible technology has become more popular, development options have also grown, and Node.js hasn’t been left behind.
In this tutorial, I’ll show you how to use Node.js to create a simple Cryptocurrency Application in Node.JS blockchain. It won’t be very fancy, but it will be just enough to help you understand how a blockchain works.
This simple form of currency will be called smashingCoin.
If you are a JavaScript developer who wants to get into the growing field of cryptocurrency, this article will give you the skills you need to get started. Or, if you want to know how things work in the world of cryptocurrencies, this tutorial may help answer some of your questions.
Prerequisites to Build a Simple Cryptocurrency Application in Node
If you want this tutorial to go smoothly, you’ll need to know a lot about:
• JavaScript
• Node.js
First, you need to have:
• You have Node.js on your machine.
• A code editor.
What’s Node.Js?
Node.js is a popular runtime environment used by well-known apps like Twitter, PayPal, and LinkedIn. Node.js uses V8, which is Google’s open-source JavaScript engine. It was made by Ryan Dahl and came out for the first time in 2011. The following are some benefits of Node.js:
Js allows asynchronous event-driven programming, eliminating processes that had to wait. This makes it easier to grow.
It is a runtime environment that works very well.
• Developers who know JavaScript can quickly learn Node.js, which makes them more productive.
• Node.js makes it easier to set up data streaming.
• The ecosystem is better by the thousands of open-source modules and tools that can be shared. It also has a strong developer community.
• open-source NoSQL databases like MongoDB use JavaScript, so a JavaScript developer can easily set these up.
Important Article: Why are Banking Systems Adopting Blockchain Development Technology?
What’s Blockchain?
Bitcoin and Ethereum are both digital currencies that use a powerful technology called the blockchain to run and be used. It uses cryptography to connect securely and keep a list of records, called blocks, constantly growing.
As the name suggests, a blockchain is a list of blocks of transaction data linked together to make a chain of transactions. Peer-to-peer rules are used to make sure that only valid transaction data is added to the blockchain network.
The chain of blocks theorem
It is a type of database that stores data in groups and has a certain amount of space to keep them. The blocks are linked to the blocks that have already been made. This makes a chain that looks like a data tree.
As the system is not centralized, the chain can’t be broken. Here, a block gets a timestamp when added to the chain.
Now, let’s make a Blockchain class that will keep this operation going:
[WRITE “0”; after the “Initial Block in the Chain” statement]
How to Make a Blockchain
Since we now have the building blocks, let’s make a class for our chain. We can explain it this way:
class BlockChain ========================
function Object() { [native code] }() {
this.blockchain = [this.startGenesisBlock()] / Start with a genesis block to create a new list of blocks.
startGenesisBlock()
return new Block({}) / Start by making a blank block.
getLatestBlock();
return this.blockchain.length – 1; / Get the final link in the chain.
addNewBlock(newBlock) / Create a new block
New Block.Prev
Hash = this.getLatestBlock().hash / Change its previous hash value to the right one.
Hash value of newBlock = newBlock.computeHash(); / Use this new value for prevHash to recalculate the hash of it.
This: this.blockchain.push(newBlock); / Join the block to our chain.
checkChainValidity() { / Check to see if all the hashes are correct, which means that the chain is valid.
for(i=1, ithis.blockchain.length, i++) / Start after the genesis block and go through each step.
constant currBlock = this .blockchain[i]
const prevBlock = this.blockchain[i -1]
Was the hash calculated correctly, or was it changed somehow?
if(currBlock.hash is not the same as currBlock.computeHash())
return false
Does it have the right prevHashvalue? That is, does it tell us what a previous block changed?
If (curry block. prewash is not the same as pre block. hash)
return false
Return true / Return true if all the blocks are valid.
Make two test blocks and put some sample data in them.
Let a = Block
(changed from “Joe” to “Jane”)
b = the new Block
(changed from “Jane” to “Joe”)
let chain = new BlockChain() / Start our chain
chain.addNewBlock(a); / Add the block a
chain.addNewBlock(b) / Add block b
console.log(chain); / Show the chain
console.log(“Valid: ” + chain.checkChainValidity()); / Check to see if our chain is real.
As you can see in the code above, I made the CryptoBlock class and added the function Object() { [native code] }() method to it, just like any other JavaScript class. Then, to set up its properties, I gave the function Object() { [native code] } method the following parameters:
Index:Â This is a unique number that keeps track of where each Block in the blockchain is.
Timestamp:Â It keeps track of when each completed transaction happened.
It gives information about the completed transactions, such as the sender’s and recipient’s reports and the amount sent or received.
precedingHash:Â It points to the Block’s hash before it is in the blockchain. This is an essential part of keeping the integrity of the blockchain.
How to check the integrity of the blockchain
As was already said, one of the most important things about a blockchain is that once a block is added to the chain, it can’t be changed without putting the rest of the chain at risk.
So, I’ll add a checkChainValidity() method to the CryptoBlockchain class to ensure the blockchain is correct.
Hashes are essential for ensuring a blockchain is valid and secure because if the information in a block changes, a new soup will be made, making the blockchain invalid.
Since this is the case, the checkChainValidity() method will use if statements to see if the hash of each Block has been changed. Starting with the first Block that was made, it will go through the whole chain and check if it is correct. Note that the genesis block is not limited because it was written in stone.
Also, the method checks to see if the hashes of each pair of blocks that come after each other point to each other. If the blockchain’s integrity hasn’t been broken, it returns true. If there are any problems, though, it returns false.
Here is the Node.js code for the smashingCoin cryptocurrency:
const SHA256 = need(“crypto-js/sha256”);
class CryptoBlock {
builder(index, timestamp, data, precedingHash = “”)
This. the index is equal to index;
this.timestamp = timestamp;
this.data = data;
this.preceedingHash = precedingHash;
this.hash is equal to this.computeHash();
This. once equals 0;
calculateHash()
return SHA256(hash)
This page +
this.beforeHash +
This timestamp plus
JSON.stringify(this.data), plus
This. nonce
toString();
proofOfWork(difficulty) = “Yes”
whileÂ
this.hash.substring(0, difficult)!
Array(difficulty plus 1).
join(“0”)
this.nonce++;
this.hash is equal to this.computeHash();
class CryptoBlockchainÂ
function Object() { [native code] }Â
This.startGenesisBlock();
This difficulty level is 4;
startGenesisBlock() {
return new CryptoBlock(0, “01/01/2020”, “First Block in the Chain”, “0”);
getLatestBlock();
return this.blockchain.length – 1;
addNewBlock(newBlock) {
This.obtainLatestBlock().hash = newBlock.preceedingHash;
hash = newBlock.computeHash();
newBlock.proofOfWork(this.difficulty);
this.blockchain.push(newBlock);
checkChainValidity()
for I = 1, I this.blockchain.length, I > 1, i++)
currentBlock = this.blockchain[i].currentBlock;
precedingBlock = this.blockchain[i – 1];
if (currentBlock.hash is not the same as currentBlock.computeHash()), then
return false;
If (current Block.precedingHash doesn’t match the hash of the Block before it), return false;
return true;
letting smashingCoin = new CryptoBlockchain();
console.log(“smashingCoin mining is in progress. “);
smashingCoin.addNewBlock(
new CryptoBlock(1, “01/06/2020”, “n”
sender: “Iris Ljesnjanin”,
recipient: “Cosima Mielke”,
quantity: 50
smashingCoin.addNewBlock(
new CryptoBlock(2, “01/07/2020”, “n”
sender: “Vitaly Friedman,”
recipient: “Ricardo Gimenes”,
quantity: 100
console.log(JSON.stringify(smashingCoin, “,Â
Related Article: What is Blockchain Technology and How Does It Work for Real World
Do You Want to Build a Simple Cryptocurrency Application?
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