Implement card value function & tests

Author: Frumentius-Rev

implement-and-rewrite-tests/implement-tests-with-node-test/3-get-card-value.test.js

@@ -3,14 +3,36 @@ import test from "node:test";
 
 import { getCardValue } from "../implement/3-get-card-value.js";
 
-// TODO: Write tests to cover all outcomes, including throwing errors for invalid cards.
+test("Ace returns 11", () => {
+  assert.equal(getCardValue("A♠"), 11);
+});
+
+test("Face cards returns 10", () => {
+  assert.equal(getCardValue("J♣"), 10);
+  assert.equal(getCardValue("Q♦"), 10);
+  assert.equal(getCardValue("K♥"), 10);
+});
+
+test("Number cards return their numerical value", () => {
+  assert.equal(getCardValue("2♥"), 2);
+  assert.equal(getCardValue("10♥"), 10);
+});
 
 test("Valid single-digit card", () => {
   assert.equal(getCardValue("9♠"), 9);
 });
 
 test("Arbitrary non-card string", () => {
-  assert.throws(() => getCardValue("invalid"), /Expected a number followed by a suit, but got "invalid"/, "Expected clear error");
+  assert.throws(
+    () => getCardValue("invalid"),
+    /Expected a number followed by a suit, but got "invalid"/,
+    "Expected clear error"
+  );
 });
 
-// TODO: What other invalid card cases can you think of?
+test("Invalid suit throws an error", () => {
+  assert.throws(
+    () => getCardValue("9X"),
+    /Expected a number followed by a suit, but got "9X"/
+  );
+});

implement-and-rewrite-tests/implement/3-get-card-value.js

@@ -24,5 +24,34 @@
 // execute the code to ensure all tests pass.
 
 export function getCardValue(card) {
-  // TODO: Implement this function
+  const rank = card.slice(0, -1);
+  const suit = card.slice(-1);
+
+  const validRanks = [
+    "A",
+    "2",
+    "3",
+    "4",
+    "5",
+    "6",
+    "7",
+    "8",
+    "9",
+    "10",
+    "J",
+    "Q",
+    "K",
+  ];
+  const validSuits = ["♠", "♥", "♦", "♣"];
+
+  if (!validRanks.includes(rank) || !validSuits.includes(suit)) {
+    throw new Error(`Expected a number followed by a suit, but got "${card}"`);
+  }
+  if (rank === "A") {
+    return 11;
+  } else if (rank === "J" || rank === "Q" || rank === "K") {
+    return 10;
+  } else {
+    return Number(rank);
+  }
 }