implement "refillCup" method

Author: pr0fix

README.md

@@ -18,18 +18,19 @@ To install caffeinated-strings, run the following command:
 
 ## 📚 Functions
 
-| Traditional Name | Coffee Name    | Description                                                                                                          |
-| ---------------- | -------------- | -------------------------------------------------------------------------------------------------------------------- |
-| `.charAt()`      | `sipAt`        | Returns the character of a string at given index (like taking a single sip of coffee).                               |
-| `.concat()`      | `addMilk`      | Concatenates a string to another separated with delimiter (like pouring milk into a cup of coffee).                  |
-| `.includes()`    | `hasMilk`      | Returns true if given string is found within this string and false if not (like checking if coffee has milk or not). |
-| `.length`        | `brewLength`   | Returns the length of a string (how "long" the brew is).                                                             |
-| `=`              | `pourCoffee`   | Copies one string to another (like pouring coffee into a new cup).                                                   |
-| `===, >, <`      | `compareBeans` | Compares two strings (like comparing coffee beans for quality).                                                      |
-| `.indexOf()`     | `findFirstSip` | Finds the first occurrence of a **character** in a string (like the first sip of coffee).                            |
-| `.indexOf()`     | `findFlavor`   | Finds the first occurrence of a **substring** inside a string (like detecting flavors in coffee).                    |
-| `.toLowerCase()` | `coolDown`     | Transforms the string to lowercase (like cooling down a cup of coffee).                                              |
-| `.toUpperCase()` | `froth`        | Transforms the string to uppercase (like frothing the milk to create a creamy top).                                  |
+| Traditional Name | Coffee Name    | Description                                                                                                                                       |
+| ---------------- | -------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `.charAt()`      | `sipAt`        | Returns the character of a string at given index (like taking a single sip of coffee).                                                            |
+| `.concat()`      | `addMilk`      | Concatenates a string to another separated with delimiter (like pouring milk into a cup of coffee).                                               |
+| `.includes()`    | `hasMilk`      | Returns true if given string is found within this string and false if not (like checking if coffee has milk or not).                              |
+| `.length`        | `brewLength`   | Returns the length of a string (how "long" the brew is).                                                                                          |
+| `=`              | `pourCoffee`   | Copies one string to another (like pouring coffee into a new cup).                                                                                |
+| `===, >, <`      | `compareBeans` | Compares two strings (like comparing coffee beans for quality).                                                                                   |
+| `.indexOf()`     | `findFirstSip` | Finds the first occurrence of a **character** in a string (like the first sip of coffee).                                                         |
+| `.indexOf()`     | `findFlavor`   | Finds the first occurrence of a **substring** inside a string (like detecting flavors in coffee).                                                 |
+| `.repeat()`      | `refillCup`    | Constructs a new string which contains a specified number of copies of the input string (like refilling a coffee cup a specific amount of times). |
+| `.toLowerCase()` | `coolDown`     | Transforms the string to lowercase (like cooling down a cup of coffee).                                                                           |
+| `.toUpperCase()` | `froth`        | Transforms the string to uppercase (like frothing the milk to create a creamy top).                                                               |
 
 ## 🔧 Usage
 
@@ -112,16 +113,24 @@ let drink = "cappuccino";
 console.log(findFlavor(drink, "cc")); // "ccuccino"
 ```
 
-9. `coolDown(str)`
-   Transforms the string to lowercase (like cooling down a cup of coffee).
-   Returns the input in lowercase as `string`:
+9. `refillCup(str, count)`
+   Constructs a new string with copies of input string the amount of times specified. Returns the new string concatenated together:
+
+```js
+let coffee = "cappuccino ";
+console.log(refillCup(drink, 3)); // "cappuccino cappuccino cappuccino "
+```
+
+10. `coolDown(str)`
+    Transforms the string to lowercase (like cooling down a cup of coffee).
+    Returns the input in lowercase as `string`:
 
 ```js
 let drink = "ESPRESSO";
 console.log(froth(drink)); // "espresso"
 ```
 
-10. `froth(str)`
+11. `froth(str)`
     Transforms the string to uppercase (like frothing the milk to create a creamy top).
     Returns the input in uppercase as `string`:
 

src/index.ts

@@ -5,6 +5,7 @@ export { coolDown } from "./coolDown";
 export { findFirstSip } from "./findFirstSip";
 export { findFlavor } from "./findFlavor";
 export { froth } from "./froth";
+export { hasMilk } from "./hasMilk";
 export { pourCoffee } from "./pourCoffee";
+export { refillCup } from "./refillCup";
 export { sipAt } from "./sipAt";
-export { hasMilk } from "./hasMilk";

src/refillCup.ts

@@ -0,0 +1,40 @@
+/**
+ * Constructs a new string which contains the specified number of copies of the input string.
+ *
+ * @param str The input string
+ * @param count The input count
+ *
+ * @returns A string with specified number of copies of input string, concatenated together.
+ *
+ * @example
+ * ```typescript
+ * refillCup("coffee ", 2); // Returns "coffee coffee "
+ * refillCup("coffee ", -1); // Returns null
+ * refillCup("", 2); // Returns null
+ * ```
+ */
+export function refillCup(str: string, count: number): string | null {
+  if (typeof str !== "string" || typeof count !== "number" || count <= 0) {
+    return null;
+  }
+
+  let isEmpty = true;
+
+  for (const _ of str) {
+    isEmpty = false;
+    break;
+  }
+
+  if (isEmpty) {
+    return null;
+  }
+
+  let result = "";
+
+  while (count > 0) {
+    result += str;
+    count--;
+  }
+
+  return result;
+}

tests/refillCup.test.ts

@@ -0,0 +1,30 @@
+import { refillCup } from "../src/index";
+
+test("refillCup should return the correct string the right amount of times", () => {
+  expect(refillCup("coffee ", 6)).toBe(
+    "coffee coffee coffee coffee coffee coffee "
+  );
+  expect(refillCup("cappuccino", 2)).toBe("cappuccinocappuccino");
+});
+
+test("refillCup should work with extended Latin alphabets and special characters", () => {
+  expect(refillCup("café", 2)).toBe("cafécafé");
+  expect(refillCup("123!@#ääööåå", 2)).toBe("123!@#ääööåå123!@#ääööåå");
+});
+
+test("refillCup should return empty string when the input string is empty", () => {
+  expect(refillCup("", 500)).toBe(null);
+});
+
+test("refillCup should return null for count lower and equal to 0", () => {
+  expect(refillCup("coffee", -100)).toBe(null);
+});
+
+test("refillCup should return null for non string or number values", () => {
+  expect(refillCup(0 as any, "cappuccino" as any)).toBeNull();
+  expect(refillCup("cappuccino" as any, true as any)).toBeNull();
+  expect(refillCup({} as any, "cappuccino" as any)).toBeNull();
+  expect(refillCup("cappuccino" as any, [] as any)).toBeNull();
+  expect(refillCup(undefined as any, "cappuccino" as any)).toBeNull();
+  expect(refillCup("cappuccino" as any, null as any)).toBeNull();
+});