fix(utils): added title and sentence case functions

Author: BioPhoton

packages/utils/src/index.ts

@@ -100,7 +100,7 @@ export {
   kebabCaseToSentence,
   kebabCaseToCamelCase,
   formatToSentenceCase,
-} from './lib/string.js';
+} from './lib/case-conversions.js';
 export * from './lib/text-formats/index.js';
 export {
   capitalize,

packages/utils/src/lib/case-conversions.ts

@@ -0,0 +1,101 @@
+import type { CamelCaseToKebabCase } from './types.js';
+
+/**
+ * Converts a kebab-case string to camelCase.
+ * @param string - The kebab-case string to convert.
+ * @returns The camelCase string.
+ */
+export function kebabCaseToCamelCase(string: string) {
+  return string
+    .split('-')
+    .map((segment, index) =>
+      index === 0
+        ? segment
+        : segment.charAt(0).toUpperCase() + segment.slice(1),
+    )
+    .join('');
+}
+
+/**
+ * Converts a camelCase string to kebab-case.
+ * @param string - The camelCase string to convert.
+ * @returns The kebab-case string.
+ */
+export function camelCaseToKebabCase<T extends string>(
+  string: T,
+): CamelCaseToKebabCase<T> {
+  return string
+    .replace(/([A-Z])([A-Z][a-z])/g, '$1-$2') // Split between uppercase followed by uppercase+lowercase
+    .replace(/([a-z])([A-Z])/g, '$1-$2') // Split between lowercase followed by uppercase
+    .replace(/([A-Z]+)([A-Z][a-z])/g, '$1-$2') // Additional split for consecutive uppercase
+    .replace(/[\s_]+/g, '-') // Replace spaces and underscores with hyphens
+    .toLowerCase() as CamelCaseToKebabCase<T>;
+}
+
+/**
+ * Converts a string to Title Case.
+ * - Capitalizes the first letter of each major word.
+ * - Keeps articles, conjunctions, and short prepositions in lowercase unless they are the first word.
+ *
+ * @param input - The string to convert.
+ * @returns The formatted title case string.
+ */
+export function toTitleCase(input: string): string {
+  const minorWords = new Set([
+    'a',
+    'an',
+    'the',
+    'and',
+    'or',
+    'but',
+    'for',
+    'nor',
+    'on',
+    'in',
+    'at',
+    'to',
+    'by',
+    'of',
+  ]);
+
+  return input
+    .replace(/([a-z])([A-Z])/g, '$1 $2') // Split PascalCase & camelCase
+    .replace(/[_-]/g, ' ') // Replace kebab-case and snake_case with spaces
+    .replace(/(\d+)/g, ' $1 ') // Add spaces around numbers
+    .replace(/\s+/g, ' ') // Remove extra spaces
+    .trim()
+    .split(' ')
+    .map((word, index) => {
+      // Preserve uppercase acronyms (e.g., API, HTTP)
+      if (/^[A-Z]{2,}$/.test(word)) {
+        return word;
+      }
+
+      // Capitalize first word or non-minor words
+      if (index === 0 || !minorWords.has(word.toLowerCase())) {
+        return word.charAt(0).toUpperCase() + word.slice(1).toLowerCase();
+      }
+      return word.toLowerCase();
+    })
+    .join(' ');
+}
+
+/**
+ * Converts a string to Sentence Case.
+ * - Capitalizes only the first letter of the sentence.
+ * - Retains case of proper nouns.
+ *
+ * @param input - The string to convert.
+ * @returns The formatted sentence case string.
+ */
+export function toSentenceCase(input: string): string {
+  return input
+    .replace(/([a-z])([A-Z])/g, '$1 $2') // Split PascalCase & camelCase
+    .replace(/[_-]/g, ' ') // Replace kebab-case and snake_case with spaces
+    .replace(/(\d+)/g, ' $1 ') // Add spaces around numbers
+    .replace(/\s+/g, ' ') // Remove extra spaces
+    .trim()
+    .toLowerCase()
+    .replace(/^(\w)/, match => match.toUpperCase()) // Capitalize first letter
+    .replace(/\b([A-Z]{2,})\b/g, match => match); // Preserve uppercase acronyms
+}

packages/utils/src/lib/case-conversions.unit.test.ts

@@ -0,0 +1,172 @@
+import {
+  camelCaseToKebabCase,
+  kebabCaseToCamelCase,
+  toSentenceCase,
+  toTitleCase,
+} from './case-conversions.js';
+
+describe('kebabCaseToCamelCase', () => {
+  it('should convert simple kebab-case to camelCase', () => {
+    expect(kebabCaseToCamelCase('hello-world')).toBe('helloWorld');
+  });
+
+  it('should handle multiple hyphens', () => {
+    expect(kebabCaseToCamelCase('this-is-a-long-string')).toBe(
+      'thisIsALongString',
+    );
+  });
+
+  it('should preserve numbers', () => {
+    expect(kebabCaseToCamelCase('user-123-test')).toBe('user123Test');
+  });
+
+  it('should handle single word', () => {
+    expect(kebabCaseToCamelCase('hello')).toBe('hello');
+  });
+
+  it('should handle empty string', () => {
+    expect(kebabCaseToCamelCase('')).toBe('');
+  });
+});
+
+describe('camelCaseToKebabCase', () => {
+  it('should convert simple camelCase to kebab-case', () => {
+    expect(camelCaseToKebabCase('helloWorld')).toBe('hello-world');
+  });
+
+  it('should handle multiple capital letters', () => {
+    expect(camelCaseToKebabCase('thisIsALongString')).toBe(
+      'this-is-a-long-string',
+    );
+  });
+
+  it('should handle consecutive capital letters', () => {
+    expect(camelCaseToKebabCase('myXMLParser')).toBe('my-xml-parser');
+  });
+
+  it('should handle spaces and underscores', () => {
+    expect(camelCaseToKebabCase('hello_world test')).toBe('hello-world-test');
+  });
+
+  it('should handle single word', () => {
+    expect(camelCaseToKebabCase('hello')).toBe('hello');
+  });
+
+  it('should handle empty string', () => {
+    expect(camelCaseToKebabCase('')).toBe('');
+  });
+});
+
+describe('toTitleCase', () => {
+  it('should capitalize each word in a simple sentence', () => {
+    expect(toTitleCase('hello world')).toBe('Hello World');
+  });
+
+  it('should capitalize each word in a longer sentence', () => {
+    expect(toTitleCase('this is a title')).toBe('This Is a Title');
+  });
+
+  it('should convert PascalCase to title case', () => {
+    expect(toTitleCase('FormatToTitleCase')).toBe('Format to Title Case');
+  });
+
+  it('should convert camelCase to title case', () => {
+    expect(toTitleCase('thisIsTest')).toBe('This Is Test');
+  });
+
+  it('should convert kebab-case to title case', () => {
+    expect(toTitleCase('hello-world-example')).toBe('Hello World Example');
+  });
+
+  it('should convert snake_case to title case', () => {
+    expect(toTitleCase('snake_case_example')).toBe('Snake Case Example');
+  });
+
+  it('should capitalize a single word', () => {
+    expect(toTitleCase('hello')).toBe('Hello');
+  });
+
+  it('should handle numbers in words correctly', () => {
+    expect(toTitleCase('chapter1Introduction')).toBe('Chapter 1 Introduction');
+  });
+
+  it('should handle numbers in slugs correctly', () => {
+    expect(toTitleCase('version2Release')).toBe('Version 2 Release');
+  });
+
+  it('should handle acronyms properly', () => {
+    expect(toTitleCase('apiResponse')).toBe('Api Response');
+  });
+
+  it('should handle mixed-case inputs correctly', () => {
+    expect(toTitleCase('thisIs-mixed_CASE')).toBe('This Is Mixed CASE');
+  });
+
+  it('should not modify already formatted title case text', () => {
+    expect(toTitleCase('Hello World')).toBe('Hello World');
+  });
+
+  it('should return an empty string when given an empty input', () => {
+    expect(toTitleCase('')).toBe('');
+  });
+});
+
+describe('toSentenceCase', () => {
+  it('should convert a simple sentence to sentence case', () => {
+    expect(toSentenceCase('hello world')).toBe('Hello world');
+  });
+
+  it('should maintain a correctly formatted sentence', () => {
+    expect(toSentenceCase('This is a test')).toBe('This is a test');
+  });
+
+  it('should convert PascalCase to sentence case', () => {
+    expect(toSentenceCase('FormatToSentenceCase')).toBe(
+      'Format to sentence case',
+    );
+  });
+
+  it('should convert camelCase to sentence case', () => {
+    expect(toSentenceCase('thisIsTest')).toBe('This is test');
+  });
+
+  it('should convert kebab-case to sentence case', () => {
+    expect(toSentenceCase('hello-world-example')).toBe('Hello world example');
+  });
+
+  it('should convert snake_case to sentence case', () => {
+    expect(toSentenceCase('snake_case_example')).toBe('Snake case example');
+  });
+
+  it('should capitalize a single word', () => {
+    expect(toSentenceCase('hello')).toBe('Hello');
+  });
+
+  it('should handle numbers in words correctly', () => {
+    expect(toSentenceCase('chapter1Introduction')).toBe(
+      'Chapter 1 introduction',
+    );
+  });
+
+  it('should handle numbers in slugs correctly', () => {
+    expect(toSentenceCase('version2Release')).toBe('Version 2 release');
+  });
+
+  it('should handle acronyms properly', () => {
+    expect(toSentenceCase('apiResponse')).toBe('Api response');
+  });
+
+  it('should handle mixed-case inputs correctly', () => {
+    expect(toSentenceCase('thisIs-mixed_CASE')).toBe('This is mixed case');
+  });
+
+  it('should not modify already formatted sentence case text', () => {
+    expect(toSentenceCase('This is a normal sentence.')).toBe(
+      'This is a normal sentence.',
+    );
+  });
+
+  it('should return an empty string when given an empty input', () => {
+    expect(toSentenceCase('')).toBe('');
+  });
+});