getObjectKeysAsUnionTypes.ts

/* ======================== EXAMPLE ONE ========================
| Made with ❤️ with TypeScript by Alvison Hunter - Nov 13th, 2024
*  =============================================================
*/
const productPrices = {
    Apple: 1.5,
    Banana: 0.5,
    Orange: 1,
    Mango: 2.5,
};

/**
 * Retrieves the price of a product.
 * 
 * @param {Extract<keyof typeof productPrices, string>} productName - The name of the product to get the price for.
 * @returns {number} The price of the specified product.
 */
const getPrice = (productName: Extract<keyof typeof productPrices, string>): number => productPrices[productName];

console.log(getPrice("Apple"));
console.log(getPrice("Banana"));
console.log(getPrice("Mango"));

/* ======================== EXAMPLE TWO ========================
| Made with ❤️ with TypeScript by Alvison Hunter - Nov 13th, 2024
*  =============================================================
*/
const PlayersWithMostBallonDOr = {
    "Leonel Messi": 8,
    "Cristiano Ronaldo": 5,
    "Michel Platini": 3,
    "Ronaldo Fenomeno": 2,
};

type PlayerNames = keyof typeof PlayersWithMostBallonDOr;

/**
 * Retrieves the number of Ballon d'Or awards a player has won.
 * 
 * @param {PlayerNames} playerName - The name of the player to query.
 * @returns {number} The number of Ballon d'Or awards the player has won.
 */
const getPlayerWithMostBallonDOr = (playerName: PlayerNames): number => {
    return PlayersWithMostBallonDOr[playerName];
};

console.log(getPlayerWithMostBallonDOr("Leonel Messi"));
console.log(getPlayerWithMostBallonDOr("Cristiano Ronaldo"));
console.log(getPlayerWithMostBallonDOr("Michel Platini"));
console.log(getPlayerWithMostBallonDOr("Ronaldo Fenomeno"));


/* ======================= EXAMPLE THREE =======================
| Made with ❤️ with TypeScript by Alvison Hunter - Nov 13th, 2024
*  =============================================================
*/
const pizzaPrices = {
    Margherita: 8.99,
    Pepperoni: 10.99,
    BBQChicken: 12.49,
    Veggie: 9.99,
    Hawaiian: 11.49,
} as const;

type PizzaName = "Margherita" | "Pepperoni" | "BBQChicken" | "Veggie" | "Hawaiian";

/**
 * Function to get the price of a pizza
 * @param pizzaName - Name of the pizza (must be a key of pizzaPrices)
 * @param isDelivery - Whether the pizza is for delivery (adds delivery charge if true)
 * @returns The price of the pizza, including delivery charge if applicable
 */
const getPizzaPrice = (pizzaName: PizzaName, isDelivery: boolean): number => {
    const basePrice = pizzaPrices[pizzaName];
    const deliveryCharge = isDelivery ? 3.5 : 0.0;
    return basePrice + deliveryCharge;
}

console.log(getPizzaPrice("Margherita", false));
console.log(getPizzaPrice("Pepperoni", true));
console.log(getPizzaPrice("Hawaiian", false));