London | 26-ITP-JAN | Abdul Moiz | Sprint 1 | Data Groups

Sprint-1/fix/median.js

@@ -6,9 +6,29 @@
 // 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;
+  // Check if input is an array
+  if (!Array.isArray(list)) {
+    return null;
+  } else {
+    // Get only numeric values
+    const numericList = list.filter((item) => typeof item === "number");
+    // Check if its empty after filtering
+    if (numericList.length === 0) {
+      return null;
+    }
+    // Sort the list by numeric value
+    numericList.sort((a, b) => a - b);
+    // Get middle index
+    const middleIndex = Math.floor(numericList.length / 2);
+    // Check if length is even or odd
+    if (numericList.length % 2 === 0) {
+      // Return average of two middle numbers
+      return (numericList[middleIndex - 1] + numericList[middleIndex]) / 2;
+    } else {
+      // Return middle number by index
+      return numericList[middleIndex];
+    }
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,23 @@
-function dedupe() {}
+function dedupe(input) {
+  // Check if the input is an array
+  if (!Array.isArray(input)) {
+    return null;
+  }
+  // Check for empty array
+  if (input.length === 0) {
+    return [];
+  }
+  // New array to hold deduped values
+  const newArray = [];
+  // Go through each element in the input array
+  for (let i = 0; i < input.length; i++) {
+    const element = input[i];
+    // If the element is not already in newArray, add it
+    if (!newArray.includes(element)) {
+      newArray.push(element);
+    }
+  }
+  return newArray;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,7 +16,6 @@ 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");
 
 // Given an array with no duplicates
 // When passed to the dedupe function
@@ -25,3 +24,23 @@ test.todo("given an empty array, it returns an empty 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
+
+describe("dedupe", () => {
+  [
+    { input: [], expected: [] },
+    { input: ["apple", "banana", 1, 10], expected: ["apple", "banana", 1, 10] },
+    {
+      input: [1, -1, -100, -100, "apple", "apple"],
+      expected: [1, -1, -100, "apple"],
+    },
+    { input: [-10, -20, -3, -4], expected: [-10, -20, -3, -4] },
+    { input: [1.5, 10.5, 0.5], expected: [1.5, 10.5, 0.5] },
+    {
+      input: ["apple", "banana", "cherry"],
+      expected: ["apple", "banana", "cherry"],
+    },
+  ].forEach(({ input, expected }) =>
+    it(`returns the deduped array for [${input}]`, () =>
+      expect(dedupe(input)).toEqual(expected))
+  );
+});

Sprint-1/implement/max.js

@@ -1,4 +1,16 @@
 function findMax(elements) {
+  // Check if input is an array
+  if (!Array.isArray(elements)) {
+    return null;
+  }
+  // Filter only numeric values
+  const numericElements = elements.filter((item) => typeof item === "number");
+  // Check if array is empty after filtering
+  if (numericElements.length === 0) {
+    return -Infinity;
+  }
+  // Return the maximum value
+  return Math.max(...numericElements);
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,7 +16,6 @@ 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");
 
 // Given an array with one number
 // When passed to the max function
@@ -41,3 +40,16 @@ test.todo("given an empty array, returns -Infinity");
 // 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
+
+describe("findMax", () => {
+  [
+    { input: ["apple", "banana", 1], expected: 1 },
+    { input: [1, -1, -100], expected: 1 },
+    { input: [-10, -20, -3, -4], expected: -3 },
+    { input: [1.5, 10.5, 0.5], expected: 10.5 },
+    { input: ["apple", "banana", "cherry"], expected: -Infinity },
+  ].forEach(({ input, expected }) =>
+    it(`returns the maximum for [${input}]`, () =>
+      expect(findMax(input)).toEqual(expected))
+  );
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,23 @@
 function sum(elements) {
+  // Check if input is an array
+  if (!Array.isArray(elements)) {
+    return null;
+  }
+  // Check if array is empty
+  if (elements.length === 0) {
+    return 0;
+  }
+  // Filter only numeric values
+  const numericElements = elements.filter((item) => typeof item === "number");
+  if (numericElements.length === 0) {
+    return -Infinity;
+  }
+  // Calculate the sum of numeric values
+  let total = 0;
+  for (let i = 0; i < numericElements.length; i++) {
+    total += numericElements[i];
+  }
+  return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,7 +13,6 @@ 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")
 
 // Given an array with just one number
 // When passed to the sum function
@@ -34,3 +33,16 @@ test.todo("given an empty array, returns 0")
 // 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
+
+describe("sum", () => {
+  [
+    { input: ["apple", "banana", 1, 10], expected: 11 },
+    { input: [1, -1, -100], expected: -100 },
+    { input: [-10, -20, -3, -4], expected: -37 },
+    { input: [1.5, 10.5, 0.5], expected: 12.5 },
+    { input: ["apple", "banana", "cherry"], expected: -Infinity },
+  ].forEach(({ input, expected }) =>
+    it(`returns the sum for [${input}]`, () =>
+      expect(sum(input)).toEqual(expected))
+  );
+});

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 element of list) {
     if (element === target) {
       return true;
     }