feat: ✨ Add StringSelection class and handy extension

fix: 🐛 Update leak tracker dependencies
test: 🧪 Add tests for StringSelection

Author: iamngoni

lib/src/string.dart

@@ -6,6 +6,115 @@
 //  Copyright (c) 2023 ModestNerds, Co
 //
 
+/// Represents a selection within a string, defined by start and end markers.
+///
+/// This class allows you to perform operations on a substring that is
+/// identified by string markers rather than integer indices.
+class StringSelection {
+  /// Creates a [StringSelection] with the given source string and selection bounds.
+  const StringSelection({
+    required this.source,
+    required this.startIndex,
+    required this.endIndex,
+  });
+
+  /// The original source string.
+  final String source;
+
+  /// The starting index of the selection (inclusive).
+  final int startIndex;
+
+  /// The ending index of the selection (exclusive).
+  final int endIndex;
+
+  /// Returns the selected substring.
+  ///
+  /// Example:
+  /// ```dart
+  /// final selection = 'Hello <b>World</b>'.select(start: '<b>', end: '</b>');
+  /// print(selection?.selected); // Output: <b>World</b>
+  /// ```
+  String get selected => source.substring(startIndex, endIndex);
+
+  /// Returns the content between the start and end markers (excluding the markers).
+  ///
+  /// Example:
+  /// ```dart
+  /// final selection = 'Hello <b>World</b>'.select(start: '<b>', end: '</b>');
+  /// print(selection?.content); // Output: World
+  /// ```
+  String content(String start, String end) {
+    return source.substring(startIndex + start.length, endIndex - end.length);
+  }
+
+  /// Returns a new string with the selected portion removed.
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = 'Hello <script>alert(1)</script> World'
+  ///     .select(start: '<script', end: '</script>')
+  ///     ?.remove();
+  /// print(result); // Output: Hello  World
+  /// ```
+  String remove() {
+    return source.substring(0, startIndex) + source.substring(endIndex);
+  }
+
+  /// Returns a new string with the selected portion replaced by [replacement].
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = 'Hello <b>World</b>'
+  ///     .select(start: '<b>', end: '</b>')
+  ///     ?.replace('Universe');
+  /// print(result); // Output: Hello Universe
+  /// ```
+  String replace(String replacement) {
+    return source.substring(0, startIndex) +
+        replacement +
+        source.substring(endIndex);
+  }
+
+  /// Returns a new string with all occurrences of the selection removed.
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = 'A<x>B<x>C'.select(start: '<x>', end: '<x>')?.removeAll();
+  /// ```
+  String removeAll(String start, String end) {
+    String result = source;
+    while (true) {
+      final selection = result.select(start: start, end: end);
+      if (selection == null) break;
+      result = selection.remove();
+    }
+    return result;
+  }
+
+  /// Returns a new string with all occurrences of the selection replaced.
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = 'A<x>1</x>B<x>2</x>C'
+  ///     .select(start: '<x>', end: '</x>')
+  ///     ?.replaceAll(start: '<x>', end: '</x>', replacement: '[]');
+  /// print(result); // Output: A[]B[]C
+  /// ```
+  String replaceAll({
+    required String start,
+    required String end,
+    required String replacement,
+  }) {
+    String result = source;
+    while (true) {
+      final selection = result.select(start: start, end: end);
+      if (selection == null) break;
+      result = selection.replace(replacement);
+    }
+    return result;
+  }
+}
+
 extension HandyStringExtension on String {
   /// Converts this string (assumed to be a country code) to a country flag emoji.
   ///
@@ -166,4 +275,42 @@ extension HandyStringExtension on String {
     inputCharacters.sort();
     return characters.join().matches(inputCharacters.join());
   }
+
+  /// Selects a portion of this string between [start] and [end] markers.
+  ///
+  /// Returns a [StringSelection] that allows you to perform operations
+  /// like [StringSelection.remove], [StringSelection.replace], etc.
+  ///
+  /// Returns `null` if the [start] or [end] markers are not found, or if
+  /// [end] appears before [start].
+  ///
+  /// Example:
+  /// ```dart
+  /// final input = 'Check - Check In: Maintenance Due : ZAR 1374.94.'
+  ///     '<script type="text/javascript">viewGLAccounts(0,2722896);</script>'
+  ///     ' Check In:';
+  ///
+  /// final result = input.select(start: '<script', end: '</script>')?.remove();
+  /// print(result);
+  /// // Output: Check - Check In: Maintenance Due : ZAR 1374.94. Check In:
+  /// ```
+  ///
+  /// Parameters:
+  ///   - [start]: The string marking the beginning of the selection.
+  ///   - [end]: The string marking the end of the selection.
+  ///
+  /// Returns a [StringSelection] or `null` if markers are not found.
+  StringSelection? select({required String start, required String end}) {
+    final startIndex = indexOf(start);
+    if (startIndex == -1) return null;
+
+    final endIndex = indexOf(end, startIndex + start.length);
+    if (endIndex == -1) return null;
+
+    return StringSelection(
+      source: this,
+      startIndex: startIndex,
+      endIndex: endIndex + end.length,
+    );
+  }
 }

pubspec.lock

@@ -63,26 +63,26 @@ packages:
     dependency: transitive
     description:
       name: leak_tracker
-      sha256: "6bb818ecbdffe216e81182c2f0714a2e62b593f4a4f13098713ff1685dfb6ab0"
+      sha256: "33e2e26bdd85a0112ec15400c8cbffea70d0f9c3407491f672a2fad47915e2de"
       url: "https://pub.dev"
     source: hosted
-    version: "10.0.9"
+    version: "11.0.2"
   leak_tracker_flutter_testing:
     dependency: transitive
     description:
       name: leak_tracker_flutter_testing
-      sha256: f8b613e7e6a13ec79cfdc0e97638fddb3ab848452eff057653abd3edba760573
+      sha256: "1dbc140bb5a23c75ea9c4811222756104fbcd1a27173f0c34ca01e16bea473c1"
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.9"
+    version: "3.0.10"
   leak_tracker_testing:
     dependency: transitive
     description:
       name: leak_tracker_testing
-      sha256: "6ba465d5d76e67ddf503e1161d1f4a6bc42306f9d66ca1e8f079a47290fb06d3"
+      sha256: "8d5a2d49f4a66b49744b23b018848400d23e54caf9463f4eb20df3eb8acb2eb1"
       url: "https://pub.dev"
     source: hosted
-    version: "3.0.1"
+    version: "3.0.2"
   matcher:
     dependency: transitive
     description:
@@ -164,18 +164,18 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: fb31f383e2ee25fbbfe06b40fe21e1e458d14080e3c67e7ba0acfde4df4e0bbd
+      sha256: "522f00f556e73044315fa4585ec3270f1808a4b186c936e612cab0b565ff1e00"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.4"
+    version: "0.7.6"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      sha256: "80b3257d1492ce4d091729e3a67a60407d227c27241d6927be0130c98e741803"
+      sha256: d530bd74fea330e6e364cda7a85019c434070188383e1cd8d9777ee586914c5b
       url: "https://pub.dev"
     source: hosted
-    version: "2.1.4"
+    version: "2.2.0"
   very_good_analysis:
     dependency: "direct dev"
     description:
@@ -193,5 +193,5 @@ packages:
     source: hosted
     version: "15.0.0"
 sdks:
-  dart: ">=3.7.0-0 <4.0.0"
+  dart: ">=3.8.0-0 <4.0.0"
   flutter: ">=3.18.0-18.0.pre.54"

test/src/string_test.dart

@@ -61,4 +61,63 @@ void main() {
       expect('HANDY EXTENSIONS'.isAllCaps, true);
     });
   });
+
+  group('select', () {
+    test('removes script tags from string', () {
+      const input = 'Check - Check In: Maintenance Due : ZAR 1374.94.'
+          '<script type="text/javascript">viewGLAccounts(0,2722896);</script>'
+          ' Check In:';
+      final result = input.select(start: '<script', end: '</script>')?.remove();
+      expect(
+          result, 'Check - Check In: Maintenance Due : ZAR 1374.94. Check In:');
+    });
+
+    test('returns null when start marker not found', () {
+      const input = 'Hello World';
+      final result = input.select(start: '<script', end: '</script>');
+      expect(result, isNull);
+    });
+
+    test('returns null when end marker not found', () {
+      const input = 'Hello <script>World';
+      final result = input.select(start: '<script>', end: '</script>');
+      expect(result, isNull);
+    });
+
+    test('selected returns the full selection including markers', () {
+      const input = 'Hello <b>World</b> Goodbye';
+      final selection = input.select(start: '<b>', end: '</b>');
+      expect(selection?.selected, '<b>World</b>');
+    });
+
+    test('content returns text between markers', () {
+      const input = 'Hello <b>World</b> Goodbye';
+      final selection = input.select(start: '<b>', end: '</b>');
+      expect(selection?.content('<b>', '</b>'), 'World');
+    });
+
+    test('replace substitutes selection with new text', () {
+      const input = 'Hello <b>World</b> Goodbye';
+      final result =
+          input.select(start: '<b>', end: '</b>')?.replace('Universe');
+      expect(result, 'Hello Universe Goodbye');
+    });
+
+    test('removeAll removes all occurrences', () {
+      const input = 'A<x>1</x>B<x>2</x>C';
+      final result =
+          input.select(start: '<x>', end: '</x>')?.removeAll('<x>', '</x>');
+      expect(result, 'ABC');
+    });
+
+    test('replaceAll replaces all occurrences', () {
+      const input = 'A<x>1</x>B<x>2</x>C';
+      final result = input.select(start: '<x>', end: '</x>')?.replaceAll(
+            start: '<x>',
+            end: '</x>',
+            replacement: '[]',
+          );
+      expect(result, 'A[]B[]C');
+    });
+  });
 }