fixed issues after the feedback

Author: MehrozMunir

Sprint-1/fix/median.js

@@ -7,15 +7,23 @@
 
 function calculateMedian(list) {
   let median = null;
-  if (Array.isArray(list) && !list.every((item) => typeof item != "number")) {
-    numericList = list.filter((item) => typeof item === "number");
-    sortedList = numericList.toSorted((a, b) => a - b);
-    const middleIndex = Math.floor(sortedList.length / 2);
-    if (sortedList.length % 2 === 0) {
-      const medianArray = sortedList.splice(middleIndex - 1, 2);
-      median = (medianArray[0] + medianArray[1]) / 2;
-    } else median = sortedList.splice(middleIndex, 1)[0];
-  }
+  //return null if the list is not an array
+  if (!Array.isArray(list)) return median;
+
+  // return null if none of the items in the array is a number
+  if (!list.some((item) => typeof item === "number")) return median;
+
+  let numericArray = list.filter((item) => typeof item === "number");
+  let sortedArray = numericArray.toSorted((a, b) => a - b);
+  const middleIndex = Math.floor(sortedArray.length / 2);
+
+  //check if the number of items in the array are even or odd
+  // and then calculate the median accordingly
+  if (sortedArray.length % 2 === 0)
+    median = (sortedArray[middleIndex - 1] + sortedArray[middleIndex]) / 2;
+  else median = sortedArray[middleIndex];
+
+  if (median === null) throw new Error("Median can't be null");
   return median;
 }
 

Sprint-1/implement/dedupe.js

@@ -1,12 +1,7 @@
 function dedupe(arr) {
-  if (arr.length === 0) return arr;
-  else {
-    dedupeArray = [];
-    arr.forEach((element) => {
-      if (!dedupeArray.includes(element)) dedupeArray.push(element);
-    });
-    return dedupeArray;
-  }
+  if (!Array.isArray(arr)) throw new Error(arr + " is not an array");
+  else if (arr.length === 0) return arr;
+  else return Array.from(new Set(arr));
 }
 
 module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -47,4 +47,12 @@ describe("dedupe", () => {
     it(`returns a copy of array removing the duplicates from [${input}]`, () =>
       expect(dedupe(input)).toEqual(expected))
   );
+
+  // Given an input value that is not array could be null or undefined or just a number or string
+  // When passed to the dedupe function
+  // Then it should thrown an error
+  [null, 930, "just a string", undefined, {}].forEach((val) =>
+    it("throw an error if the input is not an array", () =>
+      expect(() => dedupe(val)).toThrow(val + " is not an array"))
+  );
 });

Sprint-1/implement/max.js

@@ -1,5 +1,6 @@
 function findMax(array) {
-  numbersArray = array.filter((value) => typeof value === "number");
+  if (!Array.isArray(array)) throw new Error(array + " is not an array");
+  let numbersArray = array.filter((value) => typeof value === "number");
   return Math.max(...numbersArray);
 }
 

Sprint-1/implement/max.test.js

@@ -104,4 +104,12 @@ describe("findMax", () => {
     it(`returns the least surprising value for only non-numbers array [${input}]`, () =>
       expect(findMax(input)).toEqual(expected))
   );
+
+  // Given an input that is not array could be null or undefined or just a number or string
+  // When passed to the findMax function
+  // Then it should thrown an error
+  [null, 930, "just a string", undefined, {}].forEach((val) =>
+    it("throw an error if the input is not an array", () =>
+      expect(() => findMax(val)).toThrow(val + " is not an array"))
+  );
 });

Sprint-1/implement/sum.js

@@ -1,9 +1,11 @@
 function sum(array) {
-  numbersArray = array.filter((value) => typeof value === "number");
-  let sum = 0;
-  numbersArray.forEach((element) => {
-    sum += element;
-  });
+  if (!Array.isArray(array)) throw new Error(array + " is not an array");
+  let numbersArray = array.filter((value) => typeof value === "number");
+  let initialValue = 0;
+  let sum = numbersArray.reduce(
+    (accumulator, currentValue) => accumulator + currentValue,
+    initialValue
+  );
   return sum;
 }
 

Sprint-1/implement/sum.test.js

@@ -75,4 +75,12 @@ describe("sum", () => {
     it(`array containing only non-number values [${input}] should should return 0`, () =>
       expect(sum(input)).toEqual(expected))
   );
+
+  // Given an input value that is not array could be null or undefined or just a number or string
+  // When passed to the sum function
+  // Then it should thrown an error
+  [null, 930, "just a string", undefined, {}].forEach((val) =>
+    it("throw an error if the input is not an array", () =>
+      expect(() => sum(val)).toThrow(val + " is not an array"))
+  );
 });

Sprint-1/stretch/aoc-2018-day1/solution.js

@@ -1,6 +1,7 @@
+const fs = require("fs"); //getting file system to read file
+
 function getFinalFrequency() {
   let finalFrequency = 0;
-  const fs = require("fs"); //getting file system to read file
 
   const data = fs.readFileSync("input.txt", "utf8");
   const numbers = data