3-get-card-value.js

// This problem involves playing cards: https://en.wikipedia.org/wiki/Standard_52-card_deck

// Implement a function getCardValue, when given a string representing a playing card,
// should return the numerical value of the card.

// A valid card string will contain a rank followed by the suit.
// The rank can be one of the following strings:
//   "A", "2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K"
// The suit can be one of the following emojis:
//   "♠", "♥", "♦", "♣"
// For example: "A♠", "2♥", "10♥", "J♣", "Q♦", "K♦".

// When the card is an ace ("A"), the function should return 11.
// When the card is a face card ("J", "Q", "K"), the function should return 10.
// When the card is a number card ("2" to "10"), the function should return its numeric value.

// When the card string is invalid (not following the above format), the function should
// throw an error.

// Acceptance criteria:
// After you have implemented the function, write tests to cover all the cases, and
// execute the code to ensure all tests pass.
function getCardValue(card) {
  // TODO: Implement this function
  if (!card || typeof card !== "string") {
    throw new Error("Invalid card");
  }
  //
  const validSuits = ["♠", "♥", "♦", "♣"];
  const suit = card.slice(-1); //takes the last character of the string.
  const rank = card.slice(0, -1); //takes everything except the last character.

  if (!validSuits.includes(suit)) {
    throw new Error("Invalid card"); // This if statement checks the suit is valid with the Array of suit we assigned
  }
  // Based on the question i get form mentor i changed the function if statement for better experience of the code.
  const cardValues = {
    A: 11,
    J: 10,
    Q: 10,
    K: 10,
    2: 2,
    3: 3,
    4: 4,
    5: 5,
    6: 6,
    7: 7,
    8: 8,
    9: 9,
    10: 10,
  }; // This is java script object that act as like lookup table for the valid card value input.

  if (cardValues[rank] !== undefined) return cardValues[rank];
  throw new Error("Invalid card");
}

module.exports = getCardValue;

// The line below allows us to load the getCardValue function into tests in other files.
// This will be useful in the "rewrite tests with jest" step.
module.exports = getCardValue;

// Helper functions to make our assertions easier to read.
function assertEquals(actualOutput, targetOutput) {
  console.assert(
    actualOutput === targetOutput,
    `Expected ${actualOutput} to equal ${targetOutput}`
  );
}

// TODO: Write tests to cover all outcomes, including throwing errors for invalid cards.
// Examples:
assertEquals(getCardValue("9♠"), 9);

// Handling invalid cards
try {
  getCardValue("invalid");

  // This line will not be reached if an error is thrown as expected
  console.error("Error was not thrown for invalid card");
} catch (e) {}

// What other invalid card cases can you think of?