feat: added capitalize algorithm

Author: JigolKa

String/Capitalize.js

@@ -0,0 +1,17 @@
+/**
+ * @function capitalize
+ * @description Will convert the first character of the string to uppercase
+ * @param {String} str - The input string
+ * @returns {String} Capitalized string
+ * @example capitalize("hello") => Hello
+ * @example capitalize("_ello") => _ello
+ */
+const capitalize = (str) => {
+  if (typeof str !== 'string') {
+    throw new Error('Argument should be string')
+  }
+
+  return str[0].toLocaleUpperCase() + str.slice(1)
+}
+
+export default capitalize

String/test/Capitalize.test.js

@@ -0,0 +1,9 @@
+import capitalize from '../Capitalize'
+
+describe('Testing the Capitalize function', () => {
+  it('returns capitalized strings', () => {
+    expect(capitalize('hello')).toBe('Hello')
+    expect(capitalize('HELLO world')).toBe('HELLO world')
+    expect(capitalize('_ello')).toBe('_ello')
+  })
+})