From 1f5cb4ffe474113f2120d301766e13ae0acd639c Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Thu, 6 Nov 2025 18:13:08 +0000
Subject: [PATCH 1/9] Feat: implement and fix array utility functions

- Fix calculateMedian to handle sorting, filtering, and edge cases
- Implement dedupe to remove duplicates while preserving order
- Implement findMax to find maximum number ignoring non-numerics
- Implement sum to calculate total ignoring non-numerics
- Fix test files by replacing test.todo with proper test implementations
---
 Sprint-1/fix/median.js            | 27 ++++++++-
 Sprint-1/implement/dedupe.js      | 20 ++++++-
 Sprint-1/implement/dedupe.test.js |  2 +
 Sprint-1/implement/max.js         | 12 ++++
 Sprint-1/implement/max.test.js    | 91 +++++++++++++++++++++----------
 Sprint-1/implement/sum.js         |  7 +++
 Sprint-1/implement/sum.test.js    | 72 +++++++++++++++++-------
 7 files changed, 178 insertions(+), 53 deletions(-)

diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index b22590bc6..abd692c1b 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -6,9 +6,30 @@
 // 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;
+  // Return null if input is not an array
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  // Filter out non-numeric values (keep only actual numbers)
+  const numbers = list.filter((item) => typeof item === "number");
+
+  // Return null if no valid numbers found
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  // Sort numbers in ascending order (create a copy to avoid mutation)
+  const sorted = [...numbers].sort((a, b) => a - b);
+  const middleIndex = Math.floor(sorted.length / 2);
+
+  // For odd-length arrays: return middle element
+  // For even-length arrays: return average of two middle elements
+  if (sorted.length % 2 === 1) {
+    return sorted[middleIndex];
+  } else {
+    return (sorted[middleIndex - 1] + sorted[middleIndex]) / 2;
+  }
 }
 
 module.exports = calculateMedian;
diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index 781e8718a..f376e2bda 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1 +1,19 @@
-function dedupe() {}
+function dedupe() {
+  // Return empty array if input is not an array
+  if (!Array.isArray(array)) {
+    return [];
+  }
+
+  // Use Set to track seen elements and filter duplicates
+  const seen = new Set();
+  const result = [];
+
+  for (const item of array) {
+    if (!seen.has(item)) {
+      seen.add(item);
+      result.push(item);
+    }
+  }
+
+  return result;
+}
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index 23e0f8638..f8d64250f 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -21,7 +21,9 @@ 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
+test.todo("given an array with no duplicates, it returns the same 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
+test.todo("given an array with duplicates, it removes the duplicates preserving the first occurence");
diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 6dd76378e..e0443510d 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,4 +1,16 @@
 function findMax(elements) {
+  // Filter out non-numeric values and convert to numbers
+  const numbers = elements
+    .filter((item) => typeof item === "number")
+    .map(Number);
+
+  // If no numbers found, return -Infinity
+  if (numbers.length === 0) {
+    return -Infinity;
+  }
+
+  // Find the maximum number
+  return Math.max(...numbers);
 }
 
 module.exports = findMax;
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index 82f18fd88..b8c3eef08 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -12,32 +12,65 @@ We have set things up already so that this file can see your function from the o
 
 const findMax = require("./max.js");
 
-// Given an empty array
-// 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
-// Then it should return that number
-
-// 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
-
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
-
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
-
-// 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", () => {
+  // Given an empty array
+  // When passed to the max function
+  // Then it should return -infinity
+  test("given an empty array, returns -Infinity", () => {
+    expect(findMax([])).toBe(-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 that number", () => {
+    expect(findMax([5])).toBe(5);
+    expect(findMax([-10])).toBe(-10);
+    expect(findMax([0])).toBe(0);
+  });
+
+  // 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", () => {
+    expect(findMax([30, 50, 10, 40])).toBe(50);
+    expect(findMax([-5, -1, -10])).toBe(-1);
+    expect(findMax([10, -5, 20, -15])).toBe(20);
+  });
+
+  // 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 just negative numbers, returns the closest to zero", () => {
+    expect(findMax([-5, -1, -10])).toBe(-1);
+    expect(findMax([-100, -50, -25])).toBe(-25);
+  });
+
+  // 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 decimal numbers, returns the largest decimal", () => {
+    expect(findMax([1.5, 2.7, 1.2])).toBe(2.7);
+    expect(findMax([0.1, 0.01, 0.001])).toBe(0.1);
+    expect(findMax([-1.5, -2.7, -1.2])).toBe(-1.2);
+  });
+
+  // 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, ignores them and returns the max number", () => {
+    expect(findMax(["hey", 10, "hi", 60, 10])).toBe(60);
+    expect(findMax([30, "hello", 50, null, undefined, 40])).toBe(50);
+    expect(findMax([true, false, 25, 15])).toBe(25);
+  });
+
+  // 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(["hello", "world"])).toBe(-Infinity);
+    expect(findMax([null, undefined])).toBe(-Infinity);
+    expect(findMax([true, false])).toBe(-Infinity);
+    expect(findMax([{}, []])).toBe(-Infinity);
+  });
+});
\ No newline at end of file
diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index 9062aafe3..ebc81d453 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,4 +1,11 @@
 function sum(elements) {
+  // Filter out non-numeric values and convert to numbers
+  const numbers = elements
+    .filter((item) => typeof item === "number")
+    .map(Number);
+
+  // Sum all numbers using reduce
+  return numbers.reduce((total, num) => total + num, 0);
 }
 
 module.exports = sum;
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index dd0a090ca..420585c16 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -8,29 +8,61 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 
 const sum = require("./sum.js");
 
-// Acceptance Criteria:
+describe("sum", () => {
+  // Given an empty array
+  // When passed to the sum function
+  // Then it should return 0
+  test("given an empty array, returns 0", () => {
+    expect(sum([])).toBe(0);
+  });
 
-// 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
+  // Then it should return that number
+  test("given an array with just one number, returns that number", () => {
+    expect(sum([5])).toBe(5);
+    expect(sum([-10])).toBe(-10);
+    expect(sum([0])).toBe(0);
+  });
 
-// 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
+  test("given an array containing negative numbers, returns correct sum", () => {
+    expect(sum([10, -5, 3])).toBe(8);
+    expect(sum([-1, -2, -3])).toBe(-6);
+    expect(sum([-10, 20, -5])).toBe(5);
+  });
 
-// Given an array containing negative numbers
-// When passed to the sum function
-// Then it should still return the correct total sum
+  // 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 numbers, returns correct sum", () => {
+    expect(sum([1.5, 2.5, 1.0])).toBe(5);
+    expect(sum([0.1, 0.2, 0.3])).toBeCloseTo(0.6);
+    expect(sum([-1.5, 2.5, -1.0])).toBe(0);
+  });
 
-// 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 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 them and returns sum of numbers", () => {
+    expect(sum(["hey", 10, "hi", 60, 10])).toBe(80);
+    expect(sum([30, "hello", 50, null, undefined, 40])).toBe(120);
+    expect(sum([true, false, 25, 15])).toBe(40);
+    expect(sum([10, "20", 30])).toBe(40); // '20' is string, not number
+  });
 
-// 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
+  // Additional test cases
+  test("given an array with only non-number values, returns 0", () => {
+    expect(sum(["hello", "world"])).toBe(0);
+    expect(sum([null, undefined])).toBe(0);
+    expect(sum([true, false])).toBe(0);
+    expect(sum([{}, []])).toBe(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
+  test("given example from requirements", () => {
+    expect(sum([10, 20, 30])).toBe(60);
+    expect(sum(["hey", 10, "hi", 60, 10])).toBe(80);
+  });
+});
\ No newline at end of file

From 34a5b177d4ba228672eb460c7335624ef33bf5b9 Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 7 Nov 2025 00:10:45 +0000
Subject: [PATCH 2/9] Implemented include files

---
 Sprint-1/refactor/includes.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 29dad81f0..977c47a4a 100644
--- a/Sprint-1/refactor/includes.js
+++ b/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;

From bd8443b359a190a97807c7cb38bb3e44063487cd Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Sat, 8 Nov 2025 15:02:55 +0000
Subject: [PATCH 3/9] Added dedupe tests and implementation to remove array
 duplicates

---
 Sprint-1/implement/dedupe.js      | 20 ++++----------------
 Sprint-1/implement/dedupe.test.js | 14 +++++++++++---
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js
index f376e2bda..ef4af83ef 100644
--- a/Sprint-1/implement/dedupe.js
+++ b/Sprint-1/implement/dedupe.js
@@ -1,19 +1,7 @@
-function dedupe() {
-  // Return empty array if input is not an array
-  if (!Array.isArray(array)) {
-    return [];
-  }
 
-  // Use Set to track seen elements and filter duplicates
-  const seen = new Set();
-  const result = [];
+function dedupe(arr) {
+  return [...new Set(arr)];
+}
 
-  for (const item of array) {
-    if (!seen.has(item)) {
-      seen.add(item);
-      result.push(item);
-    }
-  }
+module.exports = dedupe;
 
-  return result;
-}
diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index f8d64250f..0ad7b71e0 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -16,14 +16,22 @@ 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("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.todo("given an array with no duplicates, it returns the same array");
+test("given an array with no duplicates, it returns the same array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+  expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+});
 
 // 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.todo("given an array with duplicates, it removes the duplicates preserving the first occurence");
+test("given an array with duplicates, it removes the duplicates preserving the first occurrence", () => {
+  expect(dedupe(["a", "a", "b", "c", "b"])).toEqual(["a", "b", "c"]);
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});

From 3a84e6780e79573bf274ad938ce0419b850f62b5 Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 16:38:07 +0000
Subject: [PATCH 4/9] fix(median): remove unnecessary array cloning and improve
 numeric filtering

- Only keep finite numeric values using Number.isFinite()
- Remove redundant [...numbers] clone since .filter() already creates a new array
- Add clearer comments about non-mutation and sorting behavior
- Preserve expected behaviour: return null for invalid or empty numeric inputs
---
 Sprint-1/fix/median.js | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js
index abd692c1b..b30420c57 100644
--- a/Sprint-1/fix/median.js
+++ b/Sprint-1/fix/median.js
@@ -5,31 +5,29 @@
 // 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) {
-  // Return null if input is not an array
+  
   if (!Array.isArray(list)) {
     return null;
   }
 
-  // Filter out non-numeric values (keep only actual numbers)
-  const numbers = list.filter((item) => typeof item === "number");
+  const numbers = list.filter((item) => Number.isFinite(item));
 
-  // Return null if no valid numbers found
   if (numbers.length === 0) {
     return null;
   }
 
-  // Sort numbers in ascending order (create a copy to avoid mutation)
-  const sorted = [...numbers].sort((a, b) => a - b);
-  const middleIndex = Math.floor(sorted.length / 2);
+  numbers.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbers.length / 2);
 
-  // For odd-length arrays: return middle element
-  // For even-length arrays: return average of two middle elements
-  if (sorted.length % 2 === 1) {
-    return sorted[middleIndex];
+  if (numbers.length % 2 === 1) {
+    return numbers[middleIndex];
   } else {
-    return (sorted[middleIndex - 1] + sorted[middleIndex]) / 2;
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
   }
 }
 
+
 module.exports = calculateMedian;

From b837edf0d8aee804097556a71131378309f6d49c Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 17:03:24 +0000
Subject: [PATCH 5/9] Fixed dedupe.test.js

---
 Sprint-1/implement/dedupe.test.js | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js
index 0ad7b71e0..1ac155841 100644
--- a/Sprint-1/implement/dedupe.test.js
+++ b/Sprint-1/implement/dedupe.test.js
@@ -23,9 +23,18 @@ test("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
-test("given an array with no duplicates, it returns the same array", () => {
-  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
-  expect(dedupe(["a", "b", "c"])).toEqual(["a", "b", "c"]);
+test("given an array with no duplicates, it returns a copy (not the same array)", () => {
+  const arr1 = [1, 2, 3];
+  const result1 = dedupe(arr1);
+
+  expect(result1).toEqual(arr1); // values match
+  expect(result1).not.toBe(arr1); // different reference
+
+  const arr2 = ["a", "b", "c"];
+  const result2 = dedupe(arr2);
+
+  expect(result2).toEqual(arr2);
+  expect(result2).not.toBe(arr2);
 });
 
 // Given an array with strings or numbers

From f9840eb91bcf73237e791afe10a1d000bc46d85b Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 17:05:37 +0000
Subject: [PATCH 6/9] fix(max): filter only finite numbers and remove redundant
 .map(Number)

- Use typeof === "number" and Number.isFinite to keep only actual finite numbers
- Remove unnecessary .map(Number) after filtering
- Return -Infinity when no numeric values are present
- Add defensive guard for non-array inputs
---
 Sprint-1/implement/max.js | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index e0443510d..4303c2621 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,15 +1,20 @@
 function findMax(elements) {
-  // Filter out non-numeric values and convert to numbers
-  const numbers = elements
-    .filter((item) => typeof item === "number")
-    .map(Number);
+  // Guard: if input is not an array, behave defensively and return -Infinity
+  if (!Array.isArray(elements)) {
+    return -Infinity;
+  }
+
+  // Keep only actual numeric values (excludes booleans, strings, null, undefined, NaN, Infinity)
+  const numbers = elements.filter(
+    (item) => typeof item === "number" && Number.isFinite(item)
+  );
 
   // If no numbers found, return -Infinity
   if (numbers.length === 0) {
     return -Infinity;
   }
 
-  // Find the maximum number
+  // Find and return the maximum number
   return Math.max(...numbers);
 }
 

From 1005a8802b156ae151392ed7d07ef853e5d7f1e2 Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 17:36:52 +0000
Subject: [PATCH 7/9] fix(max): only consider finite numbers, remove redundant
 .map(Number)

- Filters array to keep only real numbers
- Returns -Infinity when no numbers are present
- Preserves behavior for decimals, negatives, and mixed arrays
---
 Sprint-1/implement/max.js      | 12 ++----------
 Sprint-1/implement/max.test.js |  5 ++++-
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js
index 4303c2621..7c81e4797 100644
--- a/Sprint-1/implement/max.js
+++ b/Sprint-1/implement/max.js
@@ -1,20 +1,12 @@
 function findMax(elements) {
-  // Guard: if input is not an array, behave defensively and return -Infinity
-  if (!Array.isArray(elements)) {
-    return -Infinity;
-  }
+  if (!Array.isArray(elements)) return -Infinity;
 
-  // Keep only actual numeric values (excludes booleans, strings, null, undefined, NaN, Infinity)
   const numbers = elements.filter(
     (item) => typeof item === "number" && Number.isFinite(item)
   );
 
-  // If no numbers found, return -Infinity
-  if (numbers.length === 0) {
-    return -Infinity;
-  }
+  if (numbers.length === 0) return -Infinity;
 
-  // Find and return the maximum number
   return Math.max(...numbers);
 }
 
diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js
index b8c3eef08..98c57a242 100644
--- a/Sprint-1/implement/max.test.js
+++ b/Sprint-1/implement/max.test.js
@@ -73,4 +73,7 @@ describe("findMax", () => {
     expect(findMax([true, false])).toBe(-Infinity);
     expect(findMax([{}, []])).toBe(-Infinity);
   });
-});
\ No newline at end of file
+});
+
+
+

From 0d0c1280f6d8a27b6c1b92ba6fb615c36af5b5f4 Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 17:39:27 +0000
Subject: [PATCH 8/9] fix(sum): remove redundant .map(Number) and improve
 decimal & non-number tests

- Filter now only includes finite numbers
- Decimal sums use toBeCloseTo for precision
- Removed duplicate or meaningless tests
---
 Sprint-1/implement/sum.js      |  8 ++++----
 Sprint-1/implement/sum.test.js | 31 +++++--------------------------
 2 files changed, 9 insertions(+), 30 deletions(-)

diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js
index ebc81d453..bd8f7ba1a 100644
--- a/Sprint-1/implement/sum.js
+++ b/Sprint-1/implement/sum.js
@@ -1,8 +1,8 @@
 function sum(elements) {
-  // Filter out non-numeric values and convert to numbers
-  const numbers = elements
-    .filter((item) => typeof item === "number")
-    .map(Number);
+  // Filter out only numeric values
+  const numbers = elements.filter(
+    (item) => typeof item === "number" && Number.isFinite(item)
+  );
 
   // Sum all numbers using reduce
   return numbers.reduce((total, num) => total + num, 0);
diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js
index 420585c16..a089ce0fb 100644
--- a/Sprint-1/implement/sum.test.js
+++ b/Sprint-1/implement/sum.test.js
@@ -9,60 +9,39 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 const sum = require("./sum.js");
 
 describe("sum", () => {
-  // Given an empty array
-  // When passed to the sum function
-  // Then it should return 0
   test("given an empty array, returns 0", () => {
     expect(sum([])).toBe(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 just one number, returns that number", () => {
+  test("given an array with one number, returns that number", () => {
     expect(sum([5])).toBe(5);
     expect(sum([-10])).toBe(-10);
     expect(sum([0])).toBe(0);
   });
 
-  // 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 correct sum", () => {
     expect(sum([10, -5, 3])).toBe(8);
     expect(sum([-1, -2, -3])).toBe(-6);
     expect(sum([-10, 20, -5])).toBe(5);
   });
 
-  // 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 numbers, returns correct sum", () => {
-    expect(sum([1.5, 2.5, 1.0])).toBe(5);
+    expect(sum([1.5, 2.5, 1.0])).toBeCloseTo(5);
     expect(sum([0.1, 0.2, 0.3])).toBeCloseTo(0.6);
-    expect(sum([-1.5, 2.5, -1.0])).toBe(0);
+    expect(sum([-1.5, 2.5, -1.0])).toBeCloseTo(0);
   });
 
-  // 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 them and returns sum of numbers", () => {
     expect(sum(["hey", 10, "hi", 60, 10])).toBe(80);
     expect(sum([30, "hello", 50, null, undefined, 40])).toBe(120);
     expect(sum([true, false, 25, 15])).toBe(40);
-    expect(sum([10, "20", 30])).toBe(40); // '20' is string, not number
+    expect(sum([10, "20", 30])).toBe(40); // string '20' ignored
   });
 
-  // Additional test cases
   test("given an array with only non-number values, returns 0", () => {
     expect(sum(["hello", "world"])).toBe(0);
     expect(sum([null, undefined])).toBe(0);
     expect(sum([true, false])).toBe(0);
     expect(sum([{}, []])).toBe(0);
   });
-
-  test("given example from requirements", () => {
-    expect(sum([10, 20, 30])).toBe(60);
-    expect(sum(["hey", 10, "hi", 60, 10])).toBe(80);
-  });
-});
\ No newline at end of file
+});

From 051e212ccced84f0278f68646e5a3962ef9ed23e Mon Sep 17 00:00:00 2001
From: Khor Biel <khorkoak@gmail.com>
Date: Fri, 21 Nov 2025 17:43:40 +0000
Subject: [PATCH 9/9] refactor(includes): use for...of loop and add input guard

- Replace index-based loop with a clearer for...of loop
- Return false early for non-array inputs to avoid runtime errors
- Keep behaviour identical: returns true if target found, otherwise false
---
 Sprint-1/refactor/includes.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js
index 977c47a4a..e556250ef 100644
--- a/Sprint-1/refactor/includes.js
+++ b/Sprint-1/refactor/includes.js
@@ -1,13 +1,16 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
+  if (!Array.isArray(list)) {
+    return false;
+  }
+
   for (const element of list) {
     if (element === target) {
       return true;
     }
   }
   return false;
-
 }
 
 module.exports = includes;