New base code for mempool blockchain explorerer

backend/src/api/mempool-blocks.ts

@@ -0,0 +1,97 @@
+const config = require('../../mempool-config.json');
+import { MempoolBlock, SimpleTransaction } from '../interfaces';
+
+class MempoolBlocks {
+  private mempoolBlocks: MempoolBlock[] = [];
+
+  constructor() {}
+
+  public getMempoolBlocks(): MempoolBlock[] {
+    return this.mempoolBlocks;
+  }
+
+  public updateMempoolBlocks(memPool: { [txid: string]: SimpleTransaction }): void {
+    const latestMempool = memPool;
+    const memPoolArray: SimpleTransaction[] = [];
+    for (const i in latestMempool) {
+      if (latestMempool.hasOwnProperty(i)) {
+        memPoolArray.push(latestMempool[i]);
+      }
+    }
+    memPoolArray.sort((a, b) => b.feePerVsize - a.feePerVsize);
+    const transactionsSorted = memPoolArray.filter((tx) => tx.feePerVsize);
+    this.mempoolBlocks = this.calculateMempoolBlocks(transactionsSorted);
+  }
+
+  private calculateMempoolBlocks(transactionsSorted: SimpleTransaction[]): MempoolBlock[] {
+    const mempoolBlocks: MempoolBlock[] = [];
+    let blockWeight = 0;
+    let blockSize = 0;
+    let transactions: SimpleTransaction[] = [];
+    transactionsSorted.forEach((tx) => {
+      if (blockWeight + tx.vsize < 1000000 || mempoolBlocks.length === config.DEFAULT_PROJECTED_BLOCKS_AMOUNT) {
+        blockWeight += tx.vsize;
+        blockSize += tx.size;
+        transactions.push(tx);
+      } else {
+        mempoolBlocks.push(this.dataToMempoolBlocks(transactions, blockSize, blockWeight, mempoolBlocks.length));
+        blockWeight = 0;
+        blockSize = 0;
+        transactions = [];
+      }
+    });
+    if (transactions.length) {
+      mempoolBlocks.push(this.dataToMempoolBlocks(transactions, blockSize, blockWeight, mempoolBlocks.length));
+    }
+    return mempoolBlocks;
+  }
+
+  private dataToMempoolBlocks(transactions: SimpleTransaction[], blockSize: number, blockVSize: number, blocksIndex: number): MempoolBlock {
+    let rangeLength = 3;
+    if (blocksIndex === 0) {
+      rangeLength = 8;
+    }
+    if (transactions.length > 4000) {
+      rangeLength = 5;
+    } else if (transactions.length > 10000) {
+      rangeLength = 8;
+    } else if (transactions.length > 25000) {
+      rangeLength = 10;
+    }
+    return {
+      blockSize: blockSize,
+      blockVSize: blockVSize,
+      nTx: transactions.length,
+      medianFee: this.median(transactions.map((tx) => tx.feePerVsize)),
+      feeRange: this.getFeesInRange(transactions, rangeLength),
+    };
+  }
+
+  private median(numbers: number[]) {
+    let medianNr = 0;
+    const numsLen = numbers.length;
+    numbers.sort();
+    if (numsLen % 2 === 0) {
+        medianNr = (numbers[numsLen / 2 - 1] + numbers[numsLen / 2]) / 2;
+    } else {
+        medianNr = numbers[(numsLen - 1) / 2];
+    }
+    return medianNr;
+  }
+
+  private getFeesInRange(transactions: SimpleTransaction[], rangeLength: number) {
+    const arr = [transactions[transactions.length - 1].feePerVsize];
+    const chunk = 1 / (rangeLength - 1);
+    let itemsToAdd = rangeLength - 2;
+
+    while (itemsToAdd > 0) {
+      arr.push(transactions[Math.floor(transactions.length * chunk * itemsToAdd)].feePerVsize);
+      itemsToAdd--;
+    }
+
+    arr.push(transactions[0].feePerVsize);
+    return arr;
+  }
+}
+
+export default new MempoolBlocks();