Book Image

Learn Blockchain Programming with JavaScript

By : Eric Traub
Book Image

Learn Blockchain Programming with JavaScript

By: Eric Traub

Overview of this book

Learn Blockchain Programming with JavaScript begins by giving you a clear understanding of what blockchain technology is. You’ll then set up an environment to build your very own blockchain and you’ll add various functionalities to it. By adding functionalities to your blockchain such as the ability to mine new blocks, create transactions, and secure your blockchain through a proof-of-work you’ll gain an in-depth understanding of how blockchain technology functions. As you make your way through the chapters, you’ll learn how to build an API server to interact with your blockchain and how to host your blockchain on a decentralized network. You’ll also build a consensus algorithm and use it to verify data and keep the entire blockchain network synchronized. In the concluding chapters, you’ll finish building your blockchain prototype and gain a thorough understanding of why blockchain technology is so secure and valuable. By the end of this book, you'll understand how decentralized blockchain networks function and why decentralization is such an important feature for securing a blockchain.
Table of Contents (10 chapters)

Building the getBlock method

Let's build a new method called getBlock that will take the given blockHash and search the entire blockchain for the block associated with that particular hash. In order to build the getBlock method, follow these steps:

  1. Go to the dev/blockchain.js file and after the chainIsValid method, define this new method as follows:
Blockchain.prototype.getBlock = function(blockHash) { 

};

  1. Inside this method, we want to iterate through the entire blockchain and search for the block that has a particular blockHash value. Then, this method will return that specific block to us. We're going to do all this with the help of a for loop:
Blockchain.prototype.getBlock = function(blockHash) { 
this.chain.forEach(block => {

});
};

When defining the for loop, we cycle through every single block in the blockchain.

  1. Next, inside the loop, mention...