#150 add String.isNullOrBlank and String.isNotNullOrBlank

README.md

@@ -207,6 +207,30 @@ final isBlank = ' '.isNullOrEmpty; // false
 final isLineBreak = '\n'.isNullOrEmpty; // false
 ```
 
+### .isNullOrBlank
+
+Returns `true` if the String is either `null` or blank.
+
+```dart
+final isNull = null.isNullOrBlank; // true
+final isEmpty = ''.isNullOrBlank; // true
+final isBlank = ' '.isNullOrBlank; // true
+final isLineBreak = '\n'.isNullOrBlank; // true
+final isFoo = ' foo '.isNullOrBlank; // false
+```
+
+### .isNotNullOrBlank
+
+Returns `true` if the String is neither `null` nor blank.
+
+```dart
+final isNull = null.isNullOrBlank; // true
+final isEmpty = ''.isNullOrBlank; // true
+final isBlank = ' '.isNullOrBlank; // true
+final isLineBreak = '\n'.isNullOrBlank; // true
+final isFoo = ' foo '.isNullOrBlank; // true
+```
+
 ### .isUpperCase
 
 Returns `true` if the entire string is upper case.

lib/src/string.dart

@@ -254,3 +254,13 @@ extension NullableStringIsNotNullOrEmptyExtension on String? {
   /// Returns `true` if the string is neither null nor empty.
   bool get isNotNullOrEmpty => !isNullOrEmpty;
 }
+
+extension NullableStringIsNullOrBlankExtension on String? {
+  /// Returns `true` if the string is either `null` or blank.
+  bool get isNullOrBlank => this?.isBlank ?? true;
+}
+
+extension NullableStringIsNotNullOrBlankExtension on String? {
+  /// Returns `true` if the string is neither null nor blank.
+  bool get isNotNullOrBlank => !isNullOrBlank;
+}

test/string_test.dart

@@ -161,6 +161,22 @@ void main() {
       expect('\n'.isNotNullOrEmpty, true);
     });
 
+    test('.isNullOrBlank', () {
+      expect(null.isNullOrBlank, true);
+      expect(''.isNullOrBlank, true);
+      expect(' '.isNullOrBlank, true);
+      expect('\n'.isNullOrBlank, true);
+      expect(' foo '.isNullOrBlank, false);
+    });
+
+    test('.isNotNullOrBlank', () {
+      expect(null.isNotNullOrBlank, false);
+      expect(''.isNotNullOrBlank, false);
+      expect(' '.isNotNullOrBlank, false);
+      expect('\n'.isNotNullOrBlank, false);
+      expect(' foo '.isNotNullOrBlank, true);
+    });
+
     test('.toUtf8()', () {
       expect(''.toUtf8(), []);
       expect('hello'.toUtf8(), [104, 101, 108, 108, 111]);