Daily Challenge #309 - Coffee Customization

#challenge

You're an employee at a local cafe.

You can serve 3 coffee recipes:

Black = Black Coffee
Cubano = Cubano coffee + Brown sugar
Americano = Americano coffee + Milk with 0.5% fat

... and you can add a lot of extra sugar and milk in any coffee, for example:

Black coffee + Milk with 3.2% fat + Brown sugar
Cubano coffee + Brown sugar + Brown sugar + Cane sugar
Americano coffee + Milk with 3.2% fat + Cane sugar

With the following code provided for you, can you create a Coffee by implementing a CoffeeBuilder struct/class?

You can start from scratch or use the following code as a starting off point:

C++
struct Milk {
  float fat;
};

struct Sugar {
  std::string sort;
};

struct Coffee {
  std::string sort;
  std::vector<Milk> milk;
  std::vector<Sugar> sugar;
};

Rust
#[derive(Debug)]
struct Coffee {
    sort: String,
    milk: Vec<Milk>,
    sugar: Vec<Sugar>,
}

#[derive(Debug)]
struct Milk {
    fat: f32,
}

#[derive(Debug)]
struct Sugar {
    sort: String,
}

struct CoffeeBuilder {
    sort: String,
    milk: Vec<Milk>,
    sugar: Vec<Sugar>,
}

Tests

A Black coffee with sugar and milk with 3.2% fat, please.
A Cubano coffee, please.
An Americano with two brown sugars, please.

Good luck!

This challenge comes from arkada38 on CodeWars. Thank you to CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge idea for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (2)

Amin • Nov 22 '20

JavaScript

const count = (count, item) => ({ ...count, [item]: (count[item] || 0) + 1 });
const announce = callback => (announcements, [item, count]) => [...announcements, callback(item, count)];
const pluralize = (count, text) => count > 1 ? `${text}s` : text;
const coffee = (kind, sugars = [], milks = []) => ({
  addSugar: sugar => coffee(kind, [...sugars, sugar]),
  addMilk: milk => coffee(kind, sugars, [...milks, milk]),
  announce: () => {
    const sugarCount = sugars.reduce(count, {});
    const sugarAnnouncement = Object.entries(sugarCount).reduce(announce((sugar, count) => `with ${count} ${sugar} ${pluralize(count, "sugar")}`), []);
    const milkCount = milks.reduce(count, {});
    const milkAnnouncement = Object.entries(milkCount).reduce(announce((fat, count) => `with ${count} ${fat}% fat ${pluralize(count, "milk")}`), []);
    const announcements = [...sugarAnnouncement, ...milkAnnouncement];
    return announcements.length > 0 ? `One ${kind} ${announcements.join(", ")}, please.` : `One ${kind}, please.`;
  }
});

Usage

const firstOrder = 
  coffee("black coffee")
    .addSugar("regular")
    .addMilk(3.2)
    .announce();

const secondOrder = coffee("Cubano coffee").announce();

const thirdOrder = 
  coffee("Americano")
    .addSugar("brown")
    .addSugar("brown")
    .announce();

console.log(firstOrder);  // One black coffee with 1 regular sugar, with 1 3.2% fat milk, please.
console.log(secondOrder); // One Cubano coffee, please.
console.log(thirdOrder);  // One Americano with 2 brown sugars, please.