강의 링크는 여기를 클릭하세요👆

🧑 Typescript 배우기

• typescript 별거 없다고 생각했지만, 실제로 코드를 쓰기까지 오랜 시간이 걸렸다.
• Nicolas의 Nomadcoder 무료 강의를 통해 공부해보았다.
• 해당 강좌는 블록체인에 대한 기본 지식이 선행되어야 이해할 수 있을 것이다.
• 타입스크립트를 블록체인에 적용해 따라하다보니 자신감을 가질 수 있었다.
• 고마워요 니꼬!

👱‍♀️ 작성한 코드

import * as CryptoJS from "crypto-js";

class Block {
  static calculateBlockHash = (
    index: number,
    previousHash: string,
    timestamp: number,
    data: string
  ): string =>
    CryptoJS.SHA256(index + previousHash + timestamp + data).toString();

  static validateStructure = (aBlock: Block): boolean =>
    typeof aBlock.index === "number" &&
    typeof aBlock.hash === "string" &&
    typeof aBlock.previousHash === "string" &&
    typeof aBlock.timestamp === "number" &&
    typeof aBlock.data === "string";

  public index: number;
  public hash: string;
  public previousHash: string;
  public data: string;
  public timestamp: number;

  constructor(
    index: number,
    hash: string,
    previousHash: string,
    data: string,
    timestamp: number
  ) {
    this.index = index;
    this.hash = hash;
    this.previousHash = previousHash;
    this.data = data;
    this.timestamp = timestamp;
  }
}

const genesisBlock: Block = new Block(0, "2020202020202", "", "Hello", 123456);

let blockchain: Block[] = [genesisBlock];

const getBlockchain = (): Block[] => blockchain;

const getLatestBlock = (): Block => blockchain[blockchain.length - 1];

const getNewTimeStamp = (): number => Math.round(new Date().getTime() / 1000);

const createNewBlock = (data: string): Block => {
  const previousBlock: Block = getLatestBlock();
  const newIndex: number = previousBlock.index + 1;
  const newTimestamp: number = getNewTimeStamp();
  const newHash: string = Block.calculateBlockHash(
    newIndex,
    previousBlock.hash,
    newTimestamp,
    data
  );
  const newBlock: Block = new Block(
    newIndex,
    newHash,
    previousBlock.hash,
    data,
    newTimestamp
  );
  addBlock(newBlock);
  return newBlock;
};

const getHashforBlock = (aBlock: Block): string =>
  Block.calculateBlockHash(
    aBlock.index,
    aBlock.previousHash,
    aBlock.timestamp,
    aBlock.data
  );

const isBlockValid = (candidateBlock: Block, previousBlock: Block): boolean => {
  if (!Block.validateStructure(candidateBlock)) {
    return false;
  } else if (previousBlock.index + 1 !== candidateBlock.index) {
    return false;
  } else if (previousBlock.hash !== candidateBlock.previousHash) {
    return false;
  } else if (getHashforBlock(candidateBlock) !== candidateBlock.hash) {
    return false;
  } else {
    return true;
  }
};

const addBlock = (candidateBlock: Block): void => {
  if (isBlockValid(candidateBlock, getLatestBlock())) {
    blockchain.push(candidateBlock);
  }
};

createNewBlock("second block");
createNewBlock("third block");
createNewBlock("fourth block");

console.log(blockchain);

export {};