Improved step 29

Author: SharjeelSafdar

step29_web3_inspect_blocks/.gitignore

@@ -1,2 +1,5 @@
+# Node packages
 node_modules
-*.js
+
+# Build files created by TypeScript Compiler
+*.js

step29_web3_inspect_blocks/EthNetwork.ts

@@ -0,0 +1,71 @@
+import Web3 from "web3";
+
+const network = "mainnet";
+const INFURA_PROJECT_ID = "INFURA_PROJECT_ID";
+const RPC_ENDPOINT = `https://${network}.infura.io/v3/${INFURA_PROJECT_ID}`;
+
+export class EthNetwork {
+  private web3: Web3;
+
+  /**
+   * Creates an instance of EthNetwork object.
+   */
+  constructor() {
+    this.web3 = new Web3(RPC_ENDPOINT);
+  }
+
+  /**
+   * Get the number of the latest block on Ethereum Mainnet.
+   * @returns latest block number.
+   */
+  public getLatestBlockNumber = async () => {
+    return await this.web3.eth.getBlockNumber();
+  };
+
+  /**
+   * Fetch a block of given number or hash from the Ethereum Mainnet.
+   * @param block number or hash of the block.
+   * @returns a block of given number or Hash.
+   */
+  public getBlock = async (block: number | string) => {
+    return await this.web3.eth.getBlock(block);
+  };
+
+  /**
+   * Get the number of transaction in a block of given number or Hash.
+   * @param block (Optional) Hash or number of the block- default is "latest".
+   * @returns number of transactions in the block.
+   */
+  public getBlockTransactionCount = async (
+    block: string | number = "latest"
+  ) => {
+    return await this.web3.eth.getBlockTransactionCount(block);
+  };
+
+  /**
+   * Get a specific transaction from a block of given number.
+   * @param trxIndex index of the transaction in the block.
+   * @param block (Optional) Hash or number of the block- default is "latest".
+   * @returns transactions object for the required transaction.
+   */
+  public getTransactionFromBlock = async (
+    trxIndex: number,
+    block: string | number = "latest"
+  ) => {
+    return await this.web3.eth.getTransactionFromBlock(block, trxIndex);
+  };
+
+  /**
+   * Fetch a given number of latest blocks from Ethereum Mainnet.
+   * @param numberOfBlocks (Optional) number of blocks to fetch. Default is `10`.
+   */
+  public getLatestXBlocks = async (numberOfBlocks: number = 10) => {
+    const latestBlock = await this.getLatestBlockNumber();
+
+    let blocks: Array<any> = [];
+    for (let i = 0; i < numberOfBlocks; ++i) {
+      blocks.push(await this.getBlock(latestBlock - i));
+    }
+    return blocks;
+  };
+}

step29_web3_inspect_blocks/index.ts

@@ -1,25 +1,28 @@
-import { InspectBlocks } from './inspectBlocks';
-
-const blocks : InspectBlocks = new InspectBlocks();
-
-// get latest block number
-blocks.getBlockNumber().then((res)=>console.log('latest Block Number -------',res))
-
-// you can also write the block number or hash of the block to get info about a block
-
-// I am only logging the block hash here. Feel free to log other info about the block
-blocks.fetchBlock('latest').then((res)=>console.log('Block hash -------',res.hash))
-
-// get latest 10 blocks
-blocks.getBlockNumber().then((latest)=>{
-    for (let i=0; i< 10; i++){
-        blocks.fetchBlock(latest-i).then((block)=>console.log(block.number))
-    }
-})
-
-
-// number of transaction in a block
-blocks.getBlockTransactionCount('latest').then((res)=>console.log('Block transaction count -------',res))
-
-// get a particular transaction from a block. In this case we are getting the 3rd transaction from the latest block (transactions' index start from 0)
-blocks.getTransactionFromBlock('latest',2).then((res)=>console.log('Transaction info -------',res))
+import { EthNetwork } from "./EthNetwork";
+
+(async () => {
+  const network = new EthNetwork();
+
+  console.log("Latest Block Number:", await network.getLatestBlockNumber());
+
+  const blockNumber = 13101095;
+  const block = await network.getBlock(blockNumber);
+  // I am only logging the block hash here.
+  // Feel free to log other info about the block
+  console.log(`Block Hash of Block #${blockNumber}:`, block.hash);
+
+  console.log(
+    `Number of Txns in Block #${blockNumber}:`,
+    await network.getBlockTransactionCount(blockNumber)
+  );
+
+  console.log(
+    `First Transaction in Block #${blockNumber}:`,
+    (await network.getTransactionFromBlock(0, blockNumber)).hash
+  );
+
+  console.log("Number of Transactions in 10 Latest Blocks:");
+  (await network.getLatestXBlocks()).forEach(block => {
+    console.log(`Block Number ${block.number} ==>`, block.transactions.length);
+  });
+})();