Cape Town | 26-ITP-May | Shafiek Walker | Sprint 1 | Data Groups

Sprint-1/fix/median.js

@@ -6,9 +6,29 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  const numbersOnly = list.filter(
+    (item) => typeof item === "number" && Number.isFinite(item)
+  );
+
+  if (numbersOnly.length === 0) {
+    return null;
+  }
+
+  numbersOnly.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbersOnly.length / 2);
+
+  if (numbersOnly.length % 2 === 0) {
+    return (
+      numbersOnly[middleIndex - 1] + numbersOnly[middleIndex]
+    ) / 2;
+  }
+
+  return numbersOnly[middleIndex];
 }
 
-module.exports = calculateMedian;
+module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,5 @@
-function dedupe() {}
+function dedupe(array) {
+  return [...new Set(array)];
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,21 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // Given an empty array
 // When passed to the dedupe function
 // Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+test("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
+test("given an array with no duplicates, it returns a copy of the original array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+});
 
 // Given an array of strings or numbers
 // When passed to the dedupe function
 // Then it should return a new array with duplicates removed while preserving the 
 // first occurrence of each element from the original array.
+test("removes duplicate numbers while preserving the first occurrence", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,14 @@
 function findMax(elements) {
+    let max = -Infinity;
+    for (let i = 0; i < elements.length; i++) {
+        const element = elements[i];
+        if (typeof element === "number" && !isNaN(element)) {
+            if (element > max) {
+                max = element;
+            }
+        }
+    }
+    return max;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,48 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+test("given an empty array, returns -Infinity", () => {
+  expect(findMax([])).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(findMax([42])).toEqual(42);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+test("given an array with both positive and negative numbers, returns the largest", () => {
+  expect(findMax([-10, 5, -3, 8])).toEqual(8);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("given an array with just negative numbers, returns the closest to zero", () => {
+  expect(findMax([-10, -5, -3, -8])).toEqual(-3);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("given an array with decimal numbers, returns the largest", () => {
+  expect(findMax([1.5, 2.3, 1.8, 2.1])).toEqual(2.3);
+});
 
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
+test("given an array with non-number values, returns the largest number", () => {
+  expect(findMax(['hey', 10, 'hi', 60, 10])).toEqual(60);
+});
 
 // Given an array with only non-number values
 // When passed to the max function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("given an array with only non-number values, returns -Infinity", () => {
+  expect(findMax(['hello', 'world'])).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,12 @@
 function sum(elements) {
+    let total = 0;
+    for (let i = 0; i < elements.length; i++) {
+        const element = elements[i];
+        if (typeof element === "number" && !isNaN(element)) {
+            total += element;
+        }
+    }
+    return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,41 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with just one number, returns that number", () => {
+  expect(sum([42])).toEqual(42);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("given an array containing negative numbers, returns the correct total sum", () => {
+  expect(sum([-10, 5, -3, 8])).toEqual(0);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("given an array with decimal/float numbers, returns the correct total sum", () => {
+  expect(sum([1.5, 2.3, 1.8, 2.1])).toBeCloseTo(7.7);
+});
 
 // Given an array containing non-number values
 // When passed to the sum function
 // Then it should ignore the non-numerical values and return the sum of the numerical elements
+test("given an array containing non-number values, returns the sum of the numerical elements", () => {
+  expect(sum(['hey', 10, 'hi', 60, 10])).toEqual(80);
+});
 
 // Given an array with only non-number values
 // When passed to the sum function
 // Then it should return the least surprising value given how it behaves for all other inputs
+test("given an array with only non-number values, returns 0", () => {
+  expect(sum(['hello', 'world'])).toEqual(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,7 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }
@@ -11,3 +10,5 @@ function includes(list, target) {
 }
 
 module.exports = includes;
+
+