WM | 25-ITP-May | Nahom Mesfin | Sprint 1 | coursework

Sprint-1/fix/median.js

@@ -6,9 +6,21 @@
 // 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;// checks if a list is an array
+  const numbers = list.filter( x => typeof x === "number"); //keeps only numbers
+  if (numbers.length === 0) return null;
+  const sorted = numbers.slice().sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(sorted.length / 2);
+
+  let median;
+  if (sorted.length % 2 === 0) {
+    median = (sorted[middleIndex - 1] + sorted[middleIndex]) / 2;
+  }
+  else {
+    median = sorted[middleIndex];
+  }
+  return median
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,4 @@
-function dedupe() {}
+function dedupe(arr) {
+    return [... new Set(arr)];
+}
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -10,18 +10,34 @@ E.g. dedupe(['a','a','a','b','b','c']) target output: ['a','b','c']
 E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) target output: [5, 1, 2, 3, 8]
 E.g. dedupe([1, 2, 1]) target output: [1, 2]
 */
-
+describe("dedupe", () => {
+  test("given an array with duplicates, it deduplicate the elements of an array", () => {
+    expect(dedupe([1, 2, 1])).toEqual([1, 2]);
+    expect(dedupe(["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]);
+  });
 // Acceptance Criteria:
 
 // 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
+// Given an array with no duplicatesgo directly to implementing it step by step
 // When passed to the dedupe function
 // Then it should return a copy of the original array
 
 // 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("given an array with no duplicates, it returns a copy of the original array", () => {
+    expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+    expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+  });
+});
+
+
+
+

Sprint-1/implement/max.js

@@ -1,4 +1,6 @@
 function findMax(elements) {
+    const numbers = elements.filter(e => typeof e === 'number');
+    return Math.max(...numbers);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,46 @@ 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");
+describe("findMax", () => {
+  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, 20, 0, -2])).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 just negative numbers, returns the closest one to zero", () => {
+    expect(findMax([-10, -50, -3, -7])).toBe(-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 decimal number", () => {
+    expect(findMax([1.5, 2.7, 0.3, 2.6])).toBe(2.7);
+  });
 // 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 largest number", () => {
+    expect(findMax([10, "hi", 20, null, 5])).toBe(20);
+  });
 // 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(["a", "b", null, undefined])).toBe(-Infinity);
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,7 @@
 function sum(elements) {
+    return elements
+    .filter(e => typeof e === "number")
+    .reduce((total,num) => total + num, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,44 @@ 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")
+describe("sum", () => {
+  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 just one number, returns that number", () => {
+    expect(sum([4])).toBe(4);
+  });
 
 // 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, -15])).toBe(-10);
+  });
 
 // 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, 2.5, 3])).toBe(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, ignores them and returns the sum of the numerical elements", () => {
+    expect(sum([10, "hi", 20, null, 5])).toBe(35);
+  });
 
 // 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, undefined])).toBe(0);
+  });
+});

Sprint-1/refactor/includes.js

@@ -1,12 +1,10 @@
 // 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];
-    if (element === target) {
+  for(let element of list) {
+    if (element === target)
       return true;
     }
-  }
   return false;
 }