refactor: replace if-then-else flow by a single return statement (#2592)

Author: noritaka1166

src/lib/isBase32.js

@@ -16,9 +16,5 @@ export default function isBase32(str, options) {
     return crockfordBase32.test(str);
   }
 
-  const len = str.length;
-  if (len % 8 === 0 && base32.test(str)) {
-    return true;
-  }
-  return false;
+  return str.length % 8 === 0 && base32.test(str);
 }

src/lib/isBase58.js

@@ -5,8 +5,5 @@ const base58Reg = /^[A-HJ-NP-Za-km-z1-9]*$/;
 
 export default function isBase58(str) {
   assertString(str);
-  if (base58Reg.test(str)) {
-    return true;
-  }
-  return false;
+  return base58Reg.test(str);
 }

src/lib/isIBAN.js

@@ -101,11 +101,7 @@ function hasOnlyValidCountryCodes(countryCodeArray) {
   const countryCodeArrayFilteredWithObjectIbanCode = countryCodeArray
     .filter(countryCode => !(countryCode in ibanRegexThroughCountryCode));
 
-  if (countryCodeArrayFilteredWithObjectIbanCode.length > 0) {
-    return false;
-  }
-
-  return true;
+  return countryCodeArrayFilteredWithObjectIbanCode.length === 0;
 }
 
 /**

src/lib/isIdentityCard.js

@@ -217,23 +217,15 @@ const validators = {
     // sanitize user input
     const sanitized = str.trim();
 
-    // validate the data structure
-    if (!NIN.test(sanitized)) {
-      return false;
-    }
-    return true;
+    return NIN.test(sanitized);
   },
   'ar-TN': (str) => {
     const DNI = /^\d{8}$/;
 
     // sanitize user input
     const sanitized = str.trim();
 
-    // validate the data structure
-    if (!DNI.test(sanitized)) {
-      return false;
-    }
-    return true;
+    return DNI.test(sanitized);
   },
   'zh-CN': (str) => {
     const provincesAndCities = [