Reveal coinbase scriptsig and op_return scriptpubkey ascii on hover.

frontend/src/app/pipes/hex2ascii/hex2ascii.pipe.spec.ts

@@ -0,0 +1,8 @@
+import { Hex2asciiPipe } from './hex2ascii.pipe';
+
+describe('Hex2asciiPipe', () => {
+  it('create an instance', () => {
+    const pipe = new Hex2asciiPipe();
+    expect(pipe).toBeTruthy();
+  });
+});

frontend/src/app/pipes/hex2ascii/hex2ascii.pipe.ts

@@ -0,0 +1,19 @@
+import { Pipe, PipeTransform } from '@angular/core';
+
+@Pipe({
+  name: 'hex2ascii'
+})
+export class Hex2asciiPipe implements PipeTransform {
+
+  transform(hex: string): string {
+    if (!hex) {
+      return '';
+    }
+    let str = '';
+    for (let i = 0; i < hex.length; i += 2) {
+      str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
+    }
+    return str;
+  }
+
+}