London | 26-ITP-May | Jorvan White | Sprint 1 | Data Groups

Sprint-1/fix/median.js

@@ -5,10 +5,51 @@
 // 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).
 
-function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+function calculateMedian(list) { 
+  // [ 'not an array', 123, null, undefined, {}, [], ["apple", null, undefined] ]
+  if (typeof list === 'string') {
+    return null
+  }
+   if (typeof list === 'number') {
+    return null
+  }
+
+   if (list === null) {
+    return null 
+   }
+  if (typeof list === 'undefined') {
+    return null 
+  }
+
+   if (list === undefined) {
+    return null 
+  }
+  if (typeof list === 'object' && !Array.isArray(list)) {
+    return null 
+  }
+  if (Array.isArray(list) && list.length === 0){
+    return null
+  }
+   list = list.filter(element => typeof element === 'number');
+   if (list.length === 0) {
+    return null 
+   }
+   list.sort((a, b) => a - b);
+
+  if (list.length % 2 === 0){
+    const middleIndexR = Math.floor(list.length / 2);
+    const middleIndexL = middleIndexR - 1 
+   const evenMedian = (list[middleIndexL] + list[middleIndexR]) / 2;
+
+   return evenMedian
+  } else {
+    const middleIndex = Math.floor(list.length / 2);
+  const median = list[middleIndex];
+  return median; 
+  }
+
 }
 
+calculateMedian(['apple'])
+
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -27,15 +27,15 @@ describe("calculateMedian", () => {
     it(`returns the correct median for unsorted array [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );
 
-  it("doesn't modify the input array [3, 1, 2]", () => {
+   it("doesn't modify the input array [3, 1, 2]", () => {
     const list = [3, 1, 2];
     calculateMedian(list);
     expect(list).toEqual([3, 1, 2]);
   });
 
   [ 'not an array', 123, null, undefined, {}, [], ["apple", null, undefined] ].forEach(val =>
     it(`returns null for non-numeric array (${val})`, () => expect(calculateMedian(val)).toBe(null))
-  );
+ );
 
   [
     { input: [1, 2, "3", null, undefined, 4], expected: 2 },
@@ -47,4 +47,4 @@ describe("calculateMedian", () => {
   ].forEach(({ input, expected }) =>
     it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
   );
-});
+ });

Sprint-1/implement/dedupe.js

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

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,22 @@ 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 an a copy", () => {
+  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("given an array with duplicate strings and numbers, it returns the original with duplicates removed", () => {
+  expect(dedupe([1, 'apple', 'horse', 'horse', 2, 2, 3, 'bat'])).toEqual([1, 'apple', 'horse', 2, 3, 'bat']);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,8 @@
 function findMax(elements) {
+ elements = elements.filter(element => typeof element === 'number');
+      if (elements.length === 0){
+    return -Infinity;
+   }
+  return Math.max(...elements);
 }
-
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,49 @@ 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 the same number", () => {
+  expect(findMax([4])).toEqual(4);
+});
 
 // 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 number", () => {
+  expect(findMax([10, -10])).toEqual(10);
+});
 
 // 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 negative numbers, returns the number closest to zero", () => {
+  expect(findMax([-3 , -15, -4, -11])).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 negative numbers, returns the number closest to zero", () => {
+  expect(findMax([-3 , -15, -4, -11])).toEqual(-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, ignore the non numeric values and return the max", () => {
+  expect(findMax(['car', 'house', 1, 12, 'fish'])).toEqual(12);
+});
 
 // 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(['car', 'house', 'fish', 'car'])).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,17 @@
 function sum(elements) {
+  elements = elements.filter(element => typeof element === 'number');
+   if (elements.length === 0) {
+    return null;}
+
+    let total = 0;
+
+    for (let element of elements) {
+    total += element;
+    // += means to add to the current value and assign as result
+    // elements are individual items inside a collection (not just string)
+  }
+
+  return total;
 }
 
 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([])).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 one number, returns the same number", () => {
+  expect(sum([7])).toEqual(7);
+});
 
 // 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 total sum", () => {
+  expect(sum([-4, -15, -12])).toEqual(-31);
+});
 
 // 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 sum", () => {
+  expect(sum([4.1, 5.4, 7.8])).toEqual(17.3);
+});
 
 // 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 with non-number values, ignores the non-number values and returns the correct sum", () => {
+  expect(sum(['fish', 4, 'dog', 5, ,'pizza', 10])).toEqual(19);
+});
 
 // 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 of only non-numeric values, returns 0", () => {
+  expect(sum(['fish','dog','pizza'])).toEqual(0);
+});

Sprint-1/refactor/includes.js

@@ -1,13 +1,13 @@
 // 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;
     }
   }
   return false;
 }
 
+
 module.exports = includes;