Sheffield | ITP-Jan-26 | Hayriye Saricicek | Sprint 1| Module-Data-Groups

Sprint-1/fix/median.js

@@ -6,9 +6,22 @@
 // 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 numbers = list.filter(n => typeof n === "number" && !Number.isNaN(n));
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  const sorted = numbers.sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+
+  return sorted.length % 2
+    ? sorted[mid]
+    : (sorted[mid - 1] + sorted[mid]) / 2;
 }
 
-module.exports = calculateMedian;
+module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,6 @@
-function dedupe() {}
+function dedupe(arr) {
+  if (!Array.isArray(arr)) return [];
+  return [...new Set(arr)];
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,29 @@ 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.todo("given an empty array, it returns an empty array");
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+describe("dedupejs", () => {
+  test.each([
+    { input: [""], expected: [""] },
 
-// 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.
+    // Given an array with no duplicates
+    // When passed to the dedupe function
+    // Then it should return a copy of the original array
+
+    { input: [1, 2, 3], expected: [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.
+
+    { input: [1, 2, 2, 3], expected: [1, 2, 3] },
+    { input: [1, "a", 2, "a"], expected: [1, "a", 2] },
+    { input: ["b", "c", "d", "e"], expected: ["b", "c", "d", "e"] },
+  ])("removes duplicates from $input", ({ input, expected }) => {
+    const result = dedupe(input); // stores the result in a variable called result
+    expect(result).toEqual(expected); // Check that the result matches the expected output
+    expect(result).not.toBe(input); // Check that it's a new array (not the original)
+  });
+});

Sprint-1/implement/max.js

@@ -1,4 +1,26 @@
 function findMax(elements) {
+  //find largest number in an array
+  if (!Array.isArray(elements)) {
+    throw new Error("Input must be an array"); //checks input is an array if not throws error
+  }
+
+  let max = -Infinity; //starts at -Infinity so any number will be bigger
+  let foundValid = false; //starts at false and will become true if valid number found
+
+  for (const val of elements) {
+    if (!Number.isFinite(val)) continue; //skips non-numeric values
+
+    foundValid = true; //sets to true if a valid number is found
+    if (val > max) {
+      max = val; //updates max if current value is greater
+    }
+  }
+  if (!foundValid) {
+    //if no valid numbers found, returns"-Inifinity"  this includes invalid data and empty arrays
+    return -Infinity;
+  }
+
+  return max; //returns the largest number found
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,56 @@ 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.js", () => {
+  test.each([
+    { input: [], expected: -Infinity },
+    // Given an array with one number
+    // When passed to the max function
+    // Then it should return that number
 
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
+    { input: [1], expected: 1 },
 
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
+    // Given an array with both positive and negative numbers
+    // When passed to the max function
+    // Then it should return the largest number overall
 
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
+    { input: [1, 2, -3], expected: 2 },
 
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
+    // Given an array with just negative numbers
+    // When passed to the max function
+    // Then it should return the closest one to zero
 
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
+    { input: [-6, -2, -3], expected: -2 },
 
-// 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
+    // Given an array with decimal numbers
+    // When passed to the max function
+    // Then it should return the largest decimal number
+
+    { input: [3.5, 2.9, 6.3], expected: 6.3 },
+
+    // Given an array with non-number values
+    // When passed to the max function
+    // Then it should return the max and ignore non-numeric values
+
+    { input: ["a", 2, 3], expected: 3 },
+
+    // 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
+    // It will return -Infinity as it ignores all non-numeric values and returns -Infinity if no valid numbers found
+
+    { input: ["a", "!", "x"], expected: -Infinity },
+
+    //  Given an array contains a number string it will ignore the string and return the max number
+
+    { input: ["5", 2, 3], expected: 3 },
+
+
+    // Given an array contains only number strings it will rerturn -Infinity
+
+    { input: ["5", "2", "3"], expected: -Infinity },
+
+  ])("returns correct max for %o", ({ input, expected }) => {
+    expect(findMax(input)).toBe(expected);
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,21 @@
 function sum(elements) {
-}
+  // adds numbers and ignores non-numbers unless there are no valid numbers then throws error
+
+  if (!Array.isArray(elements)) {
+    throw new Error("Input must be an array"); //checks input is an array if not throws error
+  }
+
+  if (elements.length === 0) return 0; // <-- empty array returns 0
 
+  let total = 0;
+  let foundValid = false; //starts at false and will become true if valid number found
+
+  for (const val of elements) {
+    if (!Number.isFinite(val)) continue;
+    foundValid = true; // loops and checks if input valid and if valid changes foundValid to true
+    total += val; //adds number to sum
+  }
+
+  return foundValid ? total : "Invalid Input"; // if at least one valid value is found return sum if no valid number is found return Invalid Input
+}
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -7,30 +7,57 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 */
 
 const sum = require("./sum.js");
+describe("sum.js", () => {
+  test.each([
+    // Acceptance Criteria:
 
-// Acceptance Criteria:
+    // Given an empty array
+    // When passed to the sum function
+    // Then it should return 0
 
-// Given an empty array
-// When passed to the sum function
-// Then it should return 0
-test.todo("given an empty array, returns 0")
+    { input: [], expected: 0 },
 
-// Given an array with just one number
-// When passed to the sum function
-// Then it should return that number
+    // Given an array with just one number
+    // When passed to the sum function
+    // Then it should return that number
 
-// Given an array containing negative numbers
-// When passed to the sum function
-// Then it should still return the correct total sum
+    { input: [1], expected: 1 },
 
-// Given an array with decimal/float numbers
-// When passed to the sum function
-// Then it should return the correct total sum
+    // Given an array containing negative numbers
+    // When passed to the sum function
+    // Then it should still return the correct total sum
 
-// 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
+    { input: [-2, 3, 4, -6], expected: -1 },
+    { input: [4, -2], expected: 2 },
 
-// 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
+    // Given an array with decimal/float numbers
+    // When passed to the sum function
+    // Then it should return the correct total sum
+
+    { input: [2.3, 4.2, 3.5], expected: 10 },
+    { input: [4, 1.5], expected: 5.5 },
+
+    // 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
+
+    { input: ["a", 2, 5, "b"], expected: 7 },
+
+    // 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
+
+    { input: ["a", "n", "p"], expected: "Invalid Input" },
+  ])(
+    "sums all numbers from $input and expects $expected",
+    ({ input, expected }) => {
+      const result = sum(input);
+
+      if (typeof expected === "number") {
+        expect(Math.abs(result - expected)).toBeLessThan(1e-10); // for special cases of decimals to avoid precision issues
+      } else {
+        expect(result).toEqual(expected); // for non-numeric expected values, check for exact match
+      }
+    }
+  );
+});

Sprint-1/refactor/includes.js

@@ -1,12 +1,11 @@
 // 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;
 }