Birmingham | ITP-Jan | Roman Sanaye | Sprint 1 | Sprint 1 Exercises

Sprint-1/fix/median.js

@@ -6,9 +6,24 @@
 // 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) || list.length === 0) {
+    return null;
+  }
+
+  const onlyArrOfNumbers = list.filter((el) => typeof el === "number"); // to make the code safer better option is "const", as before I used "let".
+
+  if (onlyArrOfNumbers.length === 0) {
+    return null;
+  }
 
+  const sortedArr = onlyArrOfNumbers.sort((a, b) => a - b); // as we are not reassigning it then better option 'const' instead of "let".
+
+  const middleIndex = Math.floor(sortedArr.length / 2);
+
+  if (sortedArr.length % 2 === 1) {
+    return sortedArr[middleIndex];
+  } else {
+    return (sortedArr[middleIndex - 1] + sortedArr[middleIndex]) / 2;
+  }
+}
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,12 @@
-function dedupe() {}
+// start with the function;
+function dedupe(arr) {
+  if (arr.length === 0) return [];
+  const cleanArr = [];
+  for (let item of arr) {
+    if (!cleanArr.includes(item)) {
+      cleanArr.push(item);
+    }
+  }
+  return cleanArr;
+}
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -3,7 +3,7 @@ const dedupe = require("./dedupe.js");
 Dedupe Array
 
 📖 Dedupe means **deduplicate**
-
+ 
 In this kata, you will need to deduplicate the elements of an array
 
 E.g. dedupe(['a','a','a','b','b','c']) target output: ['a','b','c']
@@ -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("for empty array it should return an empty array", () => {
+  const arr = [];
+  expect(dedupe(arr)).toEqual([]);
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
+test("for array with no duplicates should return the original array", () => {
+  const arr = [1, 2, 3, 4];
+  expect(dedupe(arr)).toEqual(arr);
+});
 
 // 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", () => {
+  const arr = [1, 2, 1, 3, 4];
+  expect(dedupe(arr)).toEqual([1, 2, 3, 4]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,9 @@
+// start your function;
 function findMax(elements) {
+  if (elements.length === 0) return -Infinity;
+  let onlyNumArr = elements.filter((el) => typeof el === "number");
+  let maxNum = Math.max(...onlyNumArr);
+  return maxNum;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,55 @@ 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("if given empty array it should return Infinity", () => {
+  const elements = [];
+  expect(findMax(elements)).toEqual(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("if given 1 number, it should return that number", () => {
+  const elements = [8];
+  expect(findMax(elements)).toEqual(8);
+});
 
 // 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 value, should return largest number overall", () => {
+  const elements = [1, 3, 4, -3, -5];
+  expect(findMax(elements)).toEqual(4);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("if given all negative number it should return closest to Zero", () => {
+  const elements = [-1, -2, -4, -8];
+  expect(findMax(elements)).toEqual(-1);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("if given decimal number, should return largest decimal number", () => {
+  const elements = [1.2, 5.5, 9.1];
+  expect(findMax(elements)).toEqual(9.1);
+});
 
 // 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("if given non-number values it should return only max number", () => {
+  const elements = [2, 5, 7, "hi", "apple", 9];
+  expect(findMax(elements)).toEqual(9);
+});
 
 // 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("if given only non-number values it should return -Infinity ", () => {
+  const elements = ["a", "n", "hi"];
+  expect(findMax(elements)).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,12 @@
 function sum(elements) {
+  if (elements.length === 0) return 0;
+  let numberElement = elements.filter((el) => typeof el === "number");
+  if (numberElement.length === 0) return 0; // least surprising value;
+  let total = 0;
+  for (let num of numberElement) {
+    total += num;
+  }
+  return Number.isInteger.total ? total : Number(total.toFixed(2));
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,47 @@ 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("Empty array should be returned Zero", () => {
+  let elements = [];
+  expect(sum(elements)).toEqual(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given one number should be returned same as original", () => {
+  let elements = [5];
+  expect(sum(elements)).toEqual(5);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("negative number should return total with no effect", () => {
+  let elements = [1, 3, -2];
+  expect(sum(elements)).toEqual(2);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("decimal number should return the correct total", () => {
+  let elements = [1, 2.3, 4.5, 6];
+  expect(sum(elements)).toEqual(13.8);
+});
 
 // 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("non-number values be ignored, function still should return total", () => {
+  let elements = [1, 2, 3, "hi", "b"];
+  expect(sum(elements)).toEqual(6);
+});
 
 // 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("non-number values should return Zero", () => {
+  let elements = ["a", "d", "hi"];
+  expect(sum(elements)).toEqual(0);
+});

Sprint-1/refactor/includes.js

@@ -1,13 +1,8 @@
 // Refactor the implementation of includes to use a for...of loop
+// this new version looks great.
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
-    if (element === target) {
-      return true;
-    }
-  }
-  return false;
+  return list.includes(target) ? true : false;
 }
 
 module.exports = includes;