feat(#131): add capitalize function (#132)

CHANGELOG.md

@@ -11,9 +11,10 @@ This file was based on [this template](https://gist.github.com/juampynr/4c18214a
 ----
 ## [1.4 - New utils](https://github.com/201flaviosilva/utilidades/milestone/3)
 
-### [1.4.2] - XX-XX-2024 (WIP)
+### [1.4.2] - XX-XX-2025 (WIP)
 #### Added
-- `Arrays/isItemInCommon` - Checks if an item is in common between two arrays
+- `Arrays/isItemInCommon` - Checks if an item is in common between two arrays;
+- `Strings/capitalize` - Capitalizes the first letter of a string;
 
 
 ### [1.4.1] - 16-05-2024

src/Strings/capitalize.js

@@ -0,0 +1,23 @@
+/**
+ * Capitalizes the first letter of a string.
+ *
+ * @example
+ * capitalize("hello"); // "Hello"
+ * capitalize("world"); // "World"
+ * 
+ * @param {string} input - The string to capitalize.
+ * 
+ * @returns {string} - The capitalized string.
+ * 
+ * @throws {TypeError} - If the input is not a string.
+ * 
+ * @function capitalize
+ * @memberof Strings
+ */
+export function capitalize(input) {
+	if (typeof input !== "string") throw new TypeError("Input must be a string");
+
+	if (input.length === 0) return "";
+
+	return input.charAt(0).toUpperCase() + input.slice(1);
+}

src/Strings/index.js

@@ -0,0 +1,11 @@
+import { capitalize } from "./capitalize.js";
+
+
+/**
+ * Functions utils for strings
+ * 
+ * @namespace Strings
+ */
+export {
+	capitalize
+};

src/main.js

@@ -2,6 +2,7 @@ import * as Arrays from "./Arrays/index.js";
 import * as DataStructures from "./DataStructures/index.js";
 import * as Maths from "./Maths/index.js";
 import * as Physics from "./Physics/index.js";
+import * as Strings from "./Strings/index.js";
 
 import { EventSystem, EventSystemInstance } from "./EventSystem.js";
 import { Fibonacci, fibonacciCustomSequence, fibonacciSequence, fibonacciUntil, recursiveFibonacci } from "./Fibonacci.js";
@@ -29,6 +30,7 @@ export {
 	DataStructures,
 	Maths,
 	Physics,
+	Strings,
 
 	// Class
 	EventSystem, EventSystemInstance,

tests/Strings/allEqual.test.js

@@ -0,0 +1,27 @@
+import { Strings } from "./src/main";
+const { capitalize } = Strings;
+
+describe("Strings/capitalize.js", () => {
+	it("capitalize a lowercase word", () => {
+		expect(capitalize("beep")).toBe("Beep");
+	});
+
+	it("capitalize an already capitalized word", () => {
+		expect(capitalize("Boop")).toBe("Boop");
+	});
+
+	it("capitalize an empty string", () => {
+		expect(capitalize("")).toBe("");
+	});
+
+	it("handle strings with multiple words (only capitalize the first letter)", () => {
+		expect(capitalize("beep boop")).toBe("Beep boop");
+	});
+
+	it("throw an error for non-string input", () => {
+		expect(() => capitalize(123)).toThrow(TypeError);
+		expect(() => capitalize(null)).toThrow(TypeError);
+		expect(() => capitalize(undefined)).toThrow(TypeError);
+		expect(() => capitalize({})).toThrow(TypeError);
+	});
+});