🔧 Enhance string extension methods with improved URL validation, pattern matching, and leet transformation logic. Update documentation for clarity and consistency. Add tests for new functionality and edge cases.

Author: esentis

lib/src/nullable_string_extensions.dart

@@ -326,15 +326,15 @@ extension MiscExtensionsNullable on String? {
     }
   }
 
-  /// Checks whether the `String` is a valid URL.
+  /// Checks whether the `String` is a valid URL with a supported scheme.
   /// ### Example 1
   /// ```dart
   /// String foo = 'foo.1com';
   /// bool isUrl = foo.isUrl; // returns false
   /// ```
   /// ### Example 2
   /// ```dart
-  /// String foo = 'google.com';
+  /// String foo = 'https://google.com';
   /// bool isUrl = foo.isUrl; // returns true
   /// ```
   bool get isUrl {
@@ -967,7 +967,7 @@ extension MiscExtensionsNullable on String? {
     if (this.isBlank) {
       return this;
     }
-    if (index > this!.length) {
+    if (index >= this!.length) {
       return this;
     }
     if (index < 0) {
@@ -1338,7 +1338,7 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
 
-    if (index > this!.length) {
+    if (index >= this!.length) {
       return null;
     }
     if (index < 0) {
@@ -1900,7 +1900,7 @@ extension MiscExtensionsNullable on String? {
         return "${this ?? ''}";
       }
       if (resolvedBefore.isCloseWrapChar()) {
-        resolvedBefore = resolvedBefore.getOppositeChar() ?? resolvedBefore;
+        resolvedBefore = resolvedBefore.getOppositeChar();
       }
       resolvedAfter = resolvedBefore.getOppositeChar();
     }
@@ -2056,22 +2056,16 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
 
-    if (!this!.contains(pattern)) {
-      return '';
-    }
-
-    List<String> patternWords = pattern.split(' ');
-
-    if (patternWords.isEmpty) {
+    if (pattern.isEmpty) {
       return '';
     }
-    int indexOfLastPatternWord = this!.indexOf(patternWords.last);
 
-    if (patternWords.last.length == 0) {
+    int index = this!.indexOf(pattern);
+    if (index == -1) {
       return '';
     }
 
-    return this!.substring(0, indexOfLastPatternWord);
+    return this!.substring(0, index);
   }
 
   /// Removes everything in the `String` before the match of the [pattern].
@@ -2087,25 +2081,17 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
 
-    if (!this!.contains(pattern)) {
-      return '';
-    }
-
-    List<String> patternWords = pattern.split(' ');
-
-    if (patternWords.isEmpty) {
+    if (pattern.isEmpty) {
       return '';
     }
-    int indexOfFirstPatternWord = this!.indexOf(patternWords.first);
 
-    if (patternWords.last.length == 0) {
+    int index = this!.indexOf(pattern);
+    if (index == -1) {
       return '';
     }
 
-    return this!.substring(
-      indexOfFirstPatternWord + 1,
-      this!.length,
-    );
+    final startIndex = pattern.length == 1 ? index + pattern.length : index;
+    return this!.substring(startIndex);
   }
 
   /// Adds a `String` after the first match of the [pattern]. The [pattern] should not be `null`.
@@ -2123,24 +2109,19 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
 
-    if (!this!.contains(pattern)) {
-      return this;
-    }
-
-    List<String> patternWords = pattern.split(' ');
-
-    if (patternWords.isEmpty) {
+    if (pattern.isEmpty) {
       return '';
     }
-    int indexOfLastPatternWord = this!.indexOf(patternWords.last);
 
-    if (patternWords.last.length == 0) {
-      return '';
+    int index = this!.indexOf(pattern);
+    if (index == -1) {
+      return this;
     }
 
-    return this!.substring(0, indexOfLastPatternWord + 1) +
+    final insertionIndex = index + pattern.length;
+    return this!.substring(0, insertionIndex) +
         addition +
-        this!.substring(indexOfLastPatternWord + 1, this!.length);
+        this!.substring(insertionIndex, this!.length);
   }
 
   /// Adds a `String` before the first match of the [pattern]. The [pattern] should not be `null`.
@@ -2157,27 +2138,18 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
 
-    if (!this!.contains(pattern)) {
-      return this;
-    }
-
-    List<String> patternWords = pattern.split(' ');
-
-    if (patternWords.isEmpty) {
+    if (pattern.isEmpty) {
       return '';
     }
-    int indexOfFirstPatternWord = this!.indexOf(patternWords.first);
 
-    if (patternWords.last.length == 0) {
-      return '';
+    int index = this!.indexOf(pattern);
+    if (index == -1) {
+      return this;
     }
 
-    return this!.substring(0, indexOfFirstPatternWord) +
+    return this!.substring(0, index) +
         adition +
-        this!.substring(
-          indexOfFirstPatternWord,
-          this!.length,
-        );
+        this!.substring(index, this!.length);
   }
 
   /// Checks if the `String` matches **ANY** of the given [patterns].
@@ -2277,14 +2249,18 @@ extension MiscExtensionsNullable on String? {
       return this;
     }
     final letters = this!.split('');
-
-    final leetLetters = [];
-    letters.forEach((e) {
-      final count = StringHelpers.leetAlphabet[e].length;
-      final random = Random().nextInt(count);
-      print(StringHelpers.leetAlphabet[e][random]);
-      leetLetters.add(StringHelpers.leetAlphabet[e][random]);
-    });
+    final random = Random();
+    final leetLetters = <String>[];
+
+    for (final letter in letters) {
+      final replacements = StringHelpers.leetAlphabet[letter.toLowerCase()];
+      if (replacements is List && replacements.isNotEmpty) {
+        leetLetters
+            .add(replacements[random.nextInt(replacements.length)].toString());
+      } else {
+        leetLetters.add(letter);
+      }
+    }
 
     return leetLetters.join();
   }
@@ -2311,14 +2287,18 @@ extension MiscExtensionsNullable on String? {
     int sum = 0;
     bool alternate = false;
     for (int i = trimmed.length - 1; i >= 0; i--) {
-      List<String> nx = trimmed.toArray;
-      int n = int.parse(nx[i]);
+      final codeUnit = trimmed.codeUnitAt(i);
+      if (codeUnit < 48 || codeUnit > 57) {
+        return false;
+      }
+
+      int n = codeUnit - 48;
 
       if (alternate) {
         n *= 2;
 
         if (n > 9) {
-          n = (n % 10) + 1;
+          n -= 9;
         }
       }
       sum += n;