feat: 초기 프로젝트 설정 및 룰.md 파일 추가

api.hyungi.net/node_modules/validator/es/lib/isBase64.js

@@ -0,0 +1,20 @@
+import assertString from './util/assertString';
+import merge from './util/merge';
+var notBase64 = /[^A-Z0-9+\/=]/i;
+var urlSafeBase64 = /^[A-Z0-9_\-]*$/i;
+var defaultBase64Options = {
+  urlSafe: false
+};
+export default function isBase64(str, options) {
+  assertString(str);
+  options = merge(options, defaultBase64Options);
+  var len = str.length;
+  if (options.urlSafe) {
+    return urlSafeBase64.test(str);
+  }
+  if (len % 4 !== 0 || notBase64.test(str)) {
+    return false;
+  }
+  var firstPaddingChar = str.indexOf('=');
+  return firstPaddingChar === -1 || firstPaddingChar === len - 1 || firstPaddingChar === len - 2 && str[len - 1] === '=';
+}