Manchester | 26-ITP-May | Joanne O'Malley | Sprint 1 | Exercises

Sprint-1/fix/median.js

@@ -1,14 +1,21 @@
-// Fix this implementation
-// Start by running the tests for this function
-// If you're in the Sprint-1 directory, you can run `npm test -- fix` to run the tests in the fix directory
+function calculateMedian(arr) {
+  
+  if (!Array.isArray(arr)) return null;
 
-// Hint: Please consider scenarios when 'list' doesn't have numbers (the function is expected to return null)
-// or 'list' has mixed values (the function is expected to sort only numbers).
+  if (arr.length === 0) return null;
 
-function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
-}
+  const cleaned = arr.filter(x => typeof x === "number" && Number.isFinite(x));
+
+  if (cleaned.length === 0) return null;
+
+  const sorted = cleaned.sort((a, b) => a - b);
 
+  const mid = Math.floor(sorted.length / 2);
+
+  if (sorted.length % 2 === 1) {
+    return sorted[mid];
+  } else {
+    return (sorted[mid - 1] + sorted[mid]) / 2;
+  }
+}
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,11 @@
-function dedupe() {}
+function dedupe(arr) {
+  const array = [];
+  for (const x of arr) {
+    if (!array.includes(x)) {
+      array.push(x);
+    }
+  }
+  return array;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,7 +16,6 @@ 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");
 
 // Given an array with no duplicates
 // When passed to the dedupe function
@@ -26,3 +25,18 @@ test.todo("given an empty array, it returns an empty array");
 // 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("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
+
+test("given an array with no duplicates, it returns a copy", () => {
+  const input = [1, 2, 3];
+  expect(dedupe(input)).toEqual([1, 2, 3]);
+  expect(dedupe(input)).not.toBe(input); // ensures it's a new array
+});
+
+test("removes duplicates while preserving order", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+  expect(dedupe(["a", "a", "b", "c", "b"])).toEqual(["a", "b", "c"]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,18 @@
 function findMax(elements) {
+  const floats = elements
+    .filter(x => {
+      const str = String(x);
+      return !isNaN(str) && str !== "";
+    })
+    .map(x => Number(x));
+
+  if (floats.length === 0) {
+    return -Infinity;
+  } else {
+    return Math.max(...floats);
+  }
 }
+
+
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -1,43 +1,50 @@
-/* Find the maximum element of an array of numbers
-
-In this kata, you will need to implement a function that find the largest numerical element of an array.
-
-E.g. max([30, 50, 10, 40]), target output: 50
-E.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (sum ignores any non-numerical elements)
-
-You should implement this function in max.js, and add tests for it in this file.
-
-We have set things up already so that this file can see your function from the other file.
-*/
-
 const findMax = require("./max.js");
 
 // Given an empty array
 // 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([42])).toBe(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 positive and negative numbers, returns the largest number", () => {
+  expect(findMax([-10, 5, -3, 20, 8])).toBe(20);
+});
 
 // 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 only negative numbers, returns the closest to zero", () => {
+  expect(findMax([-8, -3, -15, -1])).toBe(-1);
+});
 
 // 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 decimal", () => {
+  expect(findMax([1.5, 3.14, 2.72, 3.13])).toBe(3.14);
+});
 
 // 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 them and returns the maximum number", () => {
+  expect(findMax(["hey", 10, "hi", 60, 10])).toBe(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", true, null, {}])).toBe(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,9 @@
 function sum(elements) {
+
+  return elements
+  .filter(x => String(x).replace("-", "").replace(".", "").match(/^\d+$/))
+  .reduce((sum, x) => sum + x, 0);
+
 }
 
 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([])).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([10])).toBe(10);
+});
 
 // 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", () => {
+  expect(sum([-10, -20, 30])).toBe(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 numbers, returns the correct total", () => {
+  expect(sum([10.5, 20.25, 5.25])).toBe(36);
+});
 
 // 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, ignores them and sums numbers only", () => {
+  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(["hello", "world", true, null])).toBe(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 item of items) {
     if (element === target) {
       return true;
     }
@@ -11,3 +10,4 @@ function includes(list, target) {
 }
 
 module.exports = includes;
+