Feature: Readable RegExp constructor

frontend/src/app/shared/common.utils.ts

@@ -119,6 +119,7 @@ export function convertRegion(input, to: 'name' | 'abbreviated'): string {
   }
 }
 
+
 export function haversineDistance(lat1: number, lon1: number, lat2: number, lon2: number): number {
   const rlat1 = lat1 * Math.PI / 180;
   const rlon1 = lon1 * Math.PI / 180;
@@ -135,4 +136,70 @@ export function haversineDistance(lat1: number, lon1: number, lat2: number, lon2
 
 export function kmToMiles(km: number): number {
   return km * 0.62137119;
-}
+}
+
+// all base58 characters
+const BASE58_CHARS = '[a-km-zA-HJ-NP-Z1-9]';
+// all bech32 characters (after the separator)
+const BECH32_CHARS = '[ac-hj-np-z02-9]';
+// All characters usable in bech32 human readable portion (before the 1 separator)
+// Note: Technically the spec says "all US ASCII characters" but in practice only alphabet is used.
+// Note: If HRP contains the separator (1) then the separator is "the last instance of separator"
+const BECH32_HRP_CHARS = '[a-zA-Z0-9]';
+// Hex characters
+const HEX_CHARS = '[a-fA-F0-9]';
+// A regex to say "A single 0 OR any number with no leading zeroes"
+// (?:            // Start a non-capturing group
+//   0            // A single 0
+//   |            // OR
+//   [1-9][0-9]*  // Any succession of numbers starting with 1-9
+// )              // End the non-capturing group.
+const ZERO_INDEX_NUMBER_CHARS = '(?:0|[1-9][0-9]*)';
+export type RegexType = 'address' | 'blockhash' | 'transaction' | 'blockheight';
+export type Network = 'testnet' | 'signet' | 'liquid' | 'bisq' | 'mainnet';
+export function getRegex(type: RegexType, network: Network): RegExp {
+  let regex = '^'; // ^ = Start of string
+  switch (type) {
+    // Match a block height number
+    // [Testing Order]: any order is fine
+    case 'blockheight':
+      regex += ZERO_INDEX_NUMBER_CHARS; // block height is a 0 indexed number
+      break;
+    // Match a 32 byte block hash in hex. Assumes at least 32 bits of difficulty.
+    // [Testing Order]: Must always be tested before 'transaction'
+    case 'blockhash':
+      regex += '0{8}'; // Starts with exactly 8 zeroes in a row
+      regex += `${HEX_CHARS}{56}`; // Continues with exactly 56 hex letters/numbers
+      break;
+    // Match a 32 byte tx hash in hex. Contains optional output index specifier.
+    // [Testing Order]: Must always be tested after 'blockhash'
+    case 'transaction':
+      regex += `${HEX_CHARS}{64}`; // Exactly 64 hex letters/numbers
+      regex += '(?:'; // Start a non-capturing group
+      regex += ':'; // 1 instances of the symbol ":"
+      regex += ZERO_INDEX_NUMBER_CHARS; // A zero indexed number
+      regex += ')?'; // End the non-capturing group. This group appears 0 or 1 times
+      break;
+    case 'address':
+      // TODO
+      switch (network) {
+        case 'mainnet':
+          break;
+        case 'testnet':
+          break;
+        case 'signet':
+          break;
+        case 'liquid':
+          break;
+        case 'bisq':
+          break;
+        default:
+          throw new Error('Invalid Network (Unreachable error in TypeScript)');
+      }
+      break;
+    default:
+      throw new Error('Invalid RegexType (Unreachable error in TypeScript)');
+  }
+  regex += '$'; // $ = End of string
+  return new RegExp(regex);
+}