feat (string): add Hidden Character Detector tool to identify and analyze hidden Unicode characters

src/pages/tools/string/hidden-character-detector/hidden-character-detector.service.test.ts

@@ -0,0 +1,188 @@
+import { expect, describe, it } from 'vitest';
+import { analyzeHiddenCharacters, main } from './service';
+import { InitialValuesType } from './types';
+
+describe('Hidden Character Detector', () => {
+  const defaultOptions: InitialValuesType = {
+    showUnicodeCodes: true,
+    highlightRTL: true,
+    showInvisibleChars: true,
+    includeZeroWidthChars: true
+  };
+
+  describe('analyzeHiddenCharacters', () => {
+    it('should detect RTL Override characters', () => {
+      const text = 'Hello\u202EWorld'; // RTL Override
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(1);
+      expect(result.hasRTLOverride).toBe(true);
+      expect(result.hiddenCharacters[0].isRTL).toBe(true);
+      expect(result.hiddenCharacters[0].unicode).toBe('U+202E');
+      expect(result.hiddenCharacters[0].name).toBe('Right-to-Left Override');
+    });
+
+    it('should detect invisible characters', () => {
+      const text = 'Hello\u200BWorld'; // Zero Width Space
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(1);
+      expect(result.hasInvisibleChars).toBe(true);
+      expect(result.hiddenCharacters[0].isInvisible).toBe(true);
+      expect(result.hiddenCharacters[0].unicode).toBe('U+200B');
+      expect(result.hiddenCharacters[0].name).toBe('Zero Width Space');
+    });
+
+    it('should detect zero-width characters', () => {
+      const text = 'Hello\u200CWorld'; // Zero Width Non-Joiner
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(1);
+      expect(result.hasZeroWidthChars).toBe(true);
+      expect(result.hiddenCharacters[0].isZeroWidth).toBe(true);
+      expect(result.hiddenCharacters[0].unicode).toBe('U+200C');
+    });
+
+    it('should detect multiple hidden characters', () => {
+      const text = 'Hello\u202E\u200BWorld'; // RTL Override + Zero Width Space
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(2);
+      expect(result.hasRTLOverride).toBe(true);
+      expect(result.hasInvisibleChars).toBe(true);
+      expect(result.hasZeroWidthChars).toBe(true);
+    });
+
+    it('should detect control characters', () => {
+      const text = 'Hello\u0000World'; // Null character
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(1);
+      expect(result.hiddenCharacters[0].category).toBe('Control Character');
+      expect(result.hiddenCharacters[0].isInvisible).toBe(true);
+    });
+
+    it('should not detect regular characters', () => {
+      const text = 'Hello World';
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(0);
+      expect(result.hasRTLOverride).toBe(false);
+      expect(result.hasInvisibleChars).toBe(false);
+      expect(result.hasZeroWidthChars).toBe(false);
+    });
+
+    it('should filter based on options', () => {
+      const text = 'Hello\u202E\u200BWorld';
+      const options: InitialValuesType = {
+        ...defaultOptions,
+        highlightRTL: false,
+        showInvisibleChars: true
+      };
+
+      const result = analyzeHiddenCharacters(text, options);
+
+      expect(result.totalHiddenChars).toBe(1); // Only invisible chars
+      expect(result.hasRTLOverride).toBe(false);
+      expect(result.hasInvisibleChars).toBe(true);
+    });
+
+    it('should provide correct character positions', () => {
+      const text = 'Hello\u202EWorld';
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.hiddenCharacters[0].position).toBe(5);
+      expect(result.hiddenCharacters[0].char).toBe('\u202E');
+    });
+  });
+
+  describe('main function', () => {
+    it('should return message when no hidden characters found', () => {
+      const text = 'Hello World';
+      const result = main(text, defaultOptions);
+
+      expect(result).toBe('No hidden characters detected in the text.');
+    });
+
+    it('should return detailed analysis when hidden characters found', () => {
+      const text = 'Hello\u202EWorld';
+      const result = main(text, defaultOptions);
+
+      expect(result).toContain('Found 1 hidden character(s):');
+      expect(result).toContain('Position 5: Right-to-Left Override (U+202E)');
+      expect(result).toContain('Category: RTL Override');
+      expect(result).toContain('⚠️  RTL Override Character');
+      expect(result).toContain('WARNING: RTL Override characters detected!');
+    });
+
+    it('should include Unicode codes when showUnicodeCodes is true', () => {
+      const text = 'Hello\u200BWorld';
+      const options: InitialValuesType = {
+        ...defaultOptions,
+        showUnicodeCodes: true
+      };
+
+      const result = main(text, options);
+
+      expect(result).toContain('Unicode: U+200B');
+    });
+
+    it('should not include Unicode codes when showUnicodeCodes is false', () => {
+      const text = 'Hello\u200BWorld';
+      const options: InitialValuesType = {
+        ...defaultOptions,
+        showUnicodeCodes: false
+      };
+
+      const result = main(text, options);
+
+      expect(result).not.toContain('Unicode: U+200B');
+    });
+
+    it('should handle multiple RTL characters', () => {
+      const text = 'Hello\u202E\u202DWorld';
+      const result = main(text, defaultOptions);
+
+      expect(result).toContain('Found 2 hidden character(s):');
+      expect(result).toContain('Right-to-Left Override');
+      expect(result).toContain('Left-to-Right Override');
+    });
+
+    it('should handle mixed character types', () => {
+      const text = 'Hello\u202E\u200B\u200CWorld';
+      const result = main(text, defaultOptions);
+
+      expect(result).toContain('Found 3 hidden character(s):');
+      expect(result).toContain('RTL Override Character');
+      expect(result).toContain('Invisible Character');
+      expect(result).toContain('Zero Width Character');
+    });
+  });
+
+  describe('edge cases', () => {
+    it('should handle empty string', () => {
+      const result = analyzeHiddenCharacters('', defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(0);
+      expect(result.originalText).toBe('');
+    });
+
+    it('should handle string with only hidden characters', () => {
+      const text = '\u202E\u200B\u200C';
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(3);
+      expect(result.hasRTLOverride).toBe(true);
+      expect(result.hasInvisibleChars).toBe(true);
+      expect(result.hasZeroWidthChars).toBe(true);
+    });
+
+    it('should handle very long strings', () => {
+      const text = 'A'.repeat(1000) + '\u202E' + 'B'.repeat(1000);
+      const result = analyzeHiddenCharacters(text, defaultOptions);
+
+      expect(result.totalHiddenChars).toBe(1);
+      expect(result.hiddenCharacters[0].position).toBe(1000);
+    });
+  });
+});