migrate to typescript

src/utils/hashPrefixTester.ts

@@ -0,0 +1,10 @@
+import {config} from '../config';
+
+const minimumPrefix = config.minimumPrefix || '3';
+const maximumPrefix = config.maximumPrefix || '32'; // Half the hash.
+
+const prefixChecker = new RegExp('^[\\da-f]{' + minimumPrefix + ',' + maximumPrefix + '}$', 'i');
+
+export function hashPrefixTester(prefix: string): boolean {
+    return prefixChecker.test(prefix);
+}