till function and testing it

Author: Nataliia74

Sprint-2/stretch/mode.js

@@ -34,3 +34,39 @@ function calculateMode(list) {
 }
 
 module.exports = calculateMode;
+
+// Refactoring
+
+function trackFrequency(list) {
+  let frequency = new Map();
+
+  for (const num of list) {
+    if (typeof num !== "number") {
+      continue;
+    }
+    if (frequency.has(num)) {
+      frequency.set(num, (frequency.get(num) || 0) + 1);
+    } else {
+      frequency.set(num, 1);
+    }
+  }
+  return frequency;
+}
+
+function findMode(frequency) {
+  let maxFreq = 0;
+  let mode = NaN;
+
+  for (const [num, freq] of frequency) {
+    if (freq > maxFreq) {
+      maxFreq = freq;
+      mode = num;
+    }
+  }
+  return mode;
+}
+
+function calculateModeRef(list) {
+  const frequency = trackFrequency(list);
+  return findMode(frequency);
+}

Sprint-2/stretch/till.js

@@ -5,27 +5,56 @@
 // Then it should return the total amount in pounds
 
 function totalTill(till) {
-  let total = 0;
-
-  for (const [coin, quantity] of Object.entries(till)) {
-    total += coin * quantity;
+  if (till === 0) {
+    return "0.00";
+  } else if (typeof till !== "object" || till === null || Array.isArray(till)) {
+    throw new Error("The input is not a valid object");
+  } else {
+    let total = 0;
+    for (let [coin, quantity] of Object.entries(till)) {
+      //transform till object into an array and
+      // looping trough coin as a key and quantity as value
+
+      if (coin.endsWith("p")) {
+        coin = Number(coin.slice(0, -1)); // rid of "p" at the end of coin
+      } else if (coin.startsWith("£")) {
+        coin = Number(coin.slice(1)) * 100; // rid of "£" at the start of coin and transform pound to coin
+        // by multiple by 100
+      } else {
+        throw new Error("Invalid coin format");
+      }
+
+      if (isNaN(coin)) {
+        throw new Error("Invalid coin format");
+      }
+      total += coin * quantity; // calculate total
+    }
+    return `£${(total / 100).toFixed(2)}`; // transform pence into pounds and round total to two decimal places
   }
-
-  return `£${total / 100}`;
 }
 
 const till = {
   "1p": 10,
   "5p": 6,
   "50p": 4,
-  "20p": 10,
+  "20p": 0,
 };
+
 const totalAmount = totalTill(till);
+console.log(totalAmount);
 
 // a) What is the target output when totalTill is called with the till object
+//A total amount in pounds: e.g. £2.40, represented by pounds and coins with two decimal places.
 
 // b) Why do we need to use Object.entries inside the for...of loop in this function?
+// We need to use the Object.entries to transform the object into an array to get the ability
+// to pull keys and values at the same time from the till object to calculate the total.
+// e.g. 1p and 10
 
 // c) What does coin * quantity evaluate to inside the for...of loop?
+// The coin and quantity evaluate to inside the for...of loop, the total pounds in pence
+// according to the type of coin in each array inside the Object.entries(till) array.
 
 // d) Write a test for this function to check it works and then fix the implementation of totalTill
+
+module.exports = totalTill;

Sprint-2/stretch/till.test.js

@@ -0,0 +1,35 @@
+const totalTill = require("./till.js");
+
+describe("edge cases for till function", () => {
+  test("given empty object", () => {
+    const currentOutput = totalTill({});
+    const targetOutput = "£0.00";
+    expect(currentOutput).toEqual(targetOutput);
+  });
+});
+
+test("given empty object", () => {
+  const currentOutput = totalTill({ "£0.1": 1, "0.20p": 10 });
+  const targetOutput = "£0.12";
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+test("given number as input throw an error", () => {
+  expect(() => totalTill(1233)).toThrow("The input is not a valid object");
+});
+
+test("given input with 0-quantities as input", () => {
+  const currentOutput = totalTill({ "1p": 0, "20p": 0 });
+  const targetOutput = "£0.00";
+  expect(currentOutput).toEqual(targetOutput);
+});
+
+test("given null as input throw an error", () => {
+  expect(() => totalTill(null)).toThrow("The input is not a valid object");
+});
+
+test("given null as input throw an error", () => {
+  expect(() => totalTill(["1p", 10, "20p", 9])).toThrow(
+    "The input is not a valid object"
+  );
+});