Manchester | 25-ITP-May | Jennifer Isidienu | Sprint 1| Data-Groups

Sprint-1/fix/median.js

@@ -6,9 +6,18 @@
 // 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 numbers = list.filter(val => typeof val === 'number' && !isNaN(val));
+
+  if (numbers.length === 0) return null;
+  const sorted = [...numbers].sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+
+  if (sorted.length % 2 === 0) {
+    return (sorted[mid - 1] + sorted[mid]) / 2;
+  } else {
+    return sorted[mid];
+  }
 }
 
-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

@@ -16,12 +16,23 @@ 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([]);
+});
 
 // 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, returns same array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+  expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+});
 
 // Given an array with strings or numbers
 // When passed to the dedupe function
 // Then it should remove the duplicate values, preserving the first occurence of each element
+test("removes duplicates and keeps first occurrence", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+  expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,10 @@
 function findMax(elements) {
+  if (!Array.isArray(elements)) return -Infinity;
+
+  const numbers = elements.filter(item => typeof item === "number");
+  if (numbers.length === 0) return -Infinity;
+
+  return Math.max(...numbers);
 }
 
-module.exports = findMax;
+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([])).toBe(-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([60])).toBe(60);
+});
 
 // 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 positive and negative numbers, returns the largest", () => {
+  expect(findMax([-10, 0, 15, -4, 7])).toBe(15);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+ test("given only negative numbers, returns the least negative", () => {
+  expect(findMax([-50, -10, -30])).toBe(-10);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("given decimal numbers, returns the largest one", () => {
+  expect(findMax([6.2, 7.5, 2.7])).toBe(7.5);
+});
 
 // 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, ignores non-number values and returns the max number", () => {
+  expect(findMax(['hey', 10, 'hi', 60, 10])).toBe(60);
+});
 
-// Given an array with only non-number values
+//  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(['hey', 'hi', 'hello'])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,10 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) 
+    return 0;
+
+  return elements
+    .filter(item => typeof item === "number")
+    .reduce((total, num) => total + num, 0);
 }
 
-module.exports = sum;
+module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,42 @@ 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);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with one number, returns that number", () => {
+  expect(sum([60])).toBe(60);
+});
 
 // 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, -15, -4])).toBe(-29);
+});
 
 // 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([6.2, 7.5, 2.7])).toBe(16.4);
+});
 
 // 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
+// Then it should ignore the non-numerical values and return 
+// the sum of the numerical elements
+test("given an array with non-number values, ignores non-number values and returns the sum", () => {
+  expect(sum(['hey', 10, 'hi', 60, 10])).toBe(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(['hey', 'hi', 'hello'])).toBe(0);
+});