Move in ui-qr as react-qr (from apps) (#164)

packages/react-qr/src/util.ts

@@ -0,0 +1,23 @@
+// Copyright 2017-2019 @polkadot/react-qr authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+export function encodeNumber (value: number): Uint8Array {
+  return new Uint8Array([value >> 8, value & 256]);
+}
+
+export function encodeString (value: string): Uint8Array {
+  const u8a = new Uint8Array(value.length);
+
+  for (let i = 0; i < value.length; i++) {
+    u8a[i] = value.charCodeAt(i);
+  }
+
+  return u8a;
+}
+
+export function decodeString (value: Uint8Array): string {
+  return value.reduce((str, code): string => {
+    return str + String.fromCharCode(code);
+  }, '');
+}