feat(capitalize): add capitalize

benchmarks/capitalize.bench.ts

@@ -0,0 +1,15 @@
+import { bench, describe } from 'vitest';
+import { capitalize as capitalizeToolkit } from 'es-toolkit';
+import { capitalize as capitalizeLodash } from 'lodash';
+
+describe('capitalize', () => {
+  bench('es-toolkit/capitalize', () => {
+    const str = 'camelCase';
+    capitalizeToolkit(str);
+  });
+
+  bench('lodash/capitalize', () => {
+    const str = 'camelCase';
+    capitalizeLodash(str);
+  });
+});

docs/.vitepress/en.mts

@@ -145,7 +145,10 @@ function sidebar(): DefaultTheme.Sidebar {
         },
         {
           text: 'String Utilities',
-          items: [{ text: 'snakeCase', link: '/reference/string/snakeCase' }],
+          items: [
+            { text: 'snakeCase', link: '/reference/string/snakeCase' },
+            { text: 'capitalize', link: '/reference/string/capitalize' },
+          ],
         },
       ],
     },

docs/.vitepress/ko.mts

@@ -144,7 +144,10 @@ function sidebar(): DefaultTheme.Sidebar {
         },
         {
           text: '문자열',
-          items: [{ text: 'snakeCase', link: '/ko/reference/string/snakeCase' }],
+          items: [
+            { text: 'snakeCase', link: '/ko/reference/string/snakeCase' },
+            { text: 'capitalize', link: '/ko/reference/string/capitalize' },
+          ],
         },
       ],
     },

docs/ko/reference/string/capitalize.md

@@ -0,0 +1,26 @@
+# capitalize
+
+문자열의 첫 번째 문자를 대문자로 변환하고 나머지 문자는 소문자로 변환합니다.
+
+## 인터페이스
+
+```typescript
+function capitalize<T extends string>(str: T): Capitalize<T>;
+```
+
+### 파라미터
+
+`str` (`T`): 대문자로 변환할 문자열.
+
+### 반환 값
+
+(`Capitalize<string>`): 대문자로 변환된 문자열.
+
+## 예시
+
+```typescript
+import { capitalize } from 'es-toolkit/string';
+
+capitalize('fred'); // returns 'Fred'
+capitalize('FRED'); // returns 'Fred'
+```

docs/reference/string/capitalize.md

@@ -0,0 +1,26 @@
+# capitalize
+
+Converts the first character of string to upper case and the remaining to lower case.
+
+## Signature
+
+```typescript
+function capitalize<T extends string>(str: T): Capitalize<T>;
+```
+
+### Parameters
+
+`str` (`T`): The string to be converted to uppercase.
+
+### Returns
+
+(`Capitalize<string>`): The capitalized string.
+
+## Examples
+
+```typescript
+import { capitalize } from 'es-toolkit/string';
+
+capitalize('fred'); // returns 'Fred'
+capitalize('FRED'); // returns 'Fred'
+```

src/string/capitalize.spec.ts

@@ -0,0 +1,32 @@
+import { describe, it, expect } from 'vitest';
+import { capitalize } from './capitalize';
+
+describe('capitalize', () => {
+  it('should converts the first character of string to upper case', async () => {
+    expect(capitalize('fred')).toEqual('Fred');
+  });
+
+  it('should converts the first character of string to upper case and the remaining to lower case.', async () => {
+    expect(capitalize('FRED')).toEqual('Fred');
+  });
+
+  it('should handle special characters correctly', async () => {
+    expect(capitalize('special@characters!')).toEqual('Special@characters!');
+  });
+
+  it('should handle hyphen correctly', async () => {
+    expect(capitalize('hyphen-text')).toEqual('Hyphen-text');
+  });
+
+  it('should handle leading whitepspace', async () => {
+    expect(capitalize(' fred')).toEqual(' fred');
+  });
+
+  it('should handle strings that are already in capitalize', async () => {
+    expect(capitalize('Fred')).toEqual('Fred');
+  });
+
+  it('should work with an empty string', async () => {
+    expect(capitalize('')).toEqual('');
+  });
+});

src/string/capitalize.ts

@@ -0,0 +1,15 @@
+/**
+ * Converts the first character of string to upper case and the remaining to lower case.
+ *
+ * @template T - Literal type of the string.
+ * @param {T} str - The string to be converted to uppercase.
+ * @returns {Capitalize<T>} - The capitalized string.
+ *
+ * @example
+ * const result = capitalize('fred') // returns 'Fred'
+ * const result2 = capitalize('FRED') // returns 'Fred'
+ */
+
+export const capitalize = <T extends string>(str: T): Capitalize<T> => {
+  return (str.charAt(0).toUpperCase() + str.slice(1).toLowerCase()) as Capitalize<T>;
+};

src/string/index.ts

@@ -1 +1,2 @@
 export { snakeCase } from './snakeCase.ts';
+export { capitalize } from './capitalize.ts';