West Midlands | ITP-Sep-25 | Ahmad Ehsas | sprint 1 | Data groups

Sprint-1/fix/median.js

@@ -6,9 +6,26 @@
 // 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; // Return null if input is not an array
+  }
+  // Filter only numeric values
+  const filteredlist = list.filter((item) => typeof item === "number");
+
+  // Return null if no numeric values are present
+  if (filteredlist.length === 0) {
+    return null;
+  }
+  // sort the numbers
+  filteredlist.sort((a, b) => a - b);
+  const middleIndex = Math.floor(filteredlist.length / 2);
+
+  // calculate and return median
+  if (filteredlist.length % 2 === 0) {
+    return (filteredlist[middleIndex - 1] + filteredlist[middleIndex]) / 2;
+  } else {
+    return filteredlist[middleIndex];
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,15 @@
-function dedupe() {}
+function dedupe(array) {
+  if (!Array.isArray(array)) {
+    return [];
+  }
+
+  const result = [];
+  for (let item of array) {
+    if (!result.includes(item)) {
+      result.push(item);
+    }
+  }
+  return result;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,7 +16,30 @@ E.g. dedupe([1, 2, 1]) target output: [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([]);
+});
+
+test("given an array with no duplicates, it returns the same array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+  expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+});
+
+test("removes duplicate from an array of numbers", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});
+
+test("removes duplicate from an array of strings", () => {
+  expect(dedupe(["a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+});
+
+test("preserves the order of first occurrences", () => {
+  expect(dedupe([3, 1, 2, 2, 1])).toEqual([3, 1, 2]);
+});
+
+test("handles mixed types correctly", () => {
+  expect(dedupe([1, "1", 1, "1"])).toEqual([1, "1"]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function

Sprint-1/implement/max.js

@@ -1,4 +1,17 @@
 function findMax(elements) {
+  const numericElements = elements.filter(
+    (elements) => typeof elements === "number"
+  ); // filter out only numeric values
+
+  // If there are no numeric values, return infinity
+  if (numericElements.length === 0) {
+    return -Infinity;
+  }
+
+  // use Math.max with spread (...) to get the maximum number
+  return Math.max(...numericElements);
+
 }
 
+
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,7 +16,33 @@ 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([])).toBe(Infinity);
+});
+
+test("given an  array with one number, return that number", () => {
+  expect(findMax([42])).toBe(42);
+});
+
+test("given positive and negative numbers, return the largest number", () => {
+  expect(findMax([3, -10, 20, 7, -4])).toBe(20);
+});
+
+test("given only negative numbers, return the closest one to zero", () => {
+  expect(findMax([-5, -10, -3, -8])).toBe(-3);
+});
+
+test("given decimal numbers, return the  largest decimal number", () => {
+  expect(findMax([1.5, 2.3, 0.4, 0.1])).toBe(2.3);
+});
+
+test("ignores non-numeric values", () => {
+  expect(findMax([10, "a", true, 50, null, 40])).toBe(50);
+});
+
+test("given only non-number values, returns -Infinity", () => {
+  expect(findMax(["a", "h", undefined, null])).toBe(Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function

Sprint-1/implement/sum.js

@@ -1,4 +1,9 @@
 function sum(elements) {
+  // Filter for numbers only
+  const numericValues = elements.filter((item) => typeof item === "number");
+
+  // Add the  numbers
+  return numericValues.reduce((total, num) => total + num, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,7 +13,13 @@ 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([])).toBe(0);
+});
+
+test("given an array with one number, return that number", () => {
+  expect(sum([42])).toBe(42);
+});
 
 // Given an array with just one number
 // When passed to the sum function
@@ -22,15 +28,26 @@ test.todo("given an empty array, returns 0")
 // 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 with negative numbers, returns the correct total sum", () => {
+  expect(sum([-10, -20, -30])).toBe(-60);
+});
 
 // 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 numbers, returns the correct total sum", () => {
+  expect(sum([1.5, 2.5, 3.5])).toBe(7.5);
+});
 
 // 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("ignores non-numeric values", () => {
+  expect(sum([10, "a", true, 50, null, 40])).toBe(100);
+});
 // 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(["a", "b", null, true])).toBe(0);
+});