From a70c42b775a2e365e02fbce80c2ded069b86cc63 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Fri, 14 Nov 2025 21:42:30 +0000 Subject: [PATCH 1/9] Fix: update calculateMedian implementation to correctly handle median calculation and improve test descriptions --- Sprint-1/fix/median.js | 20 +++++++++++++++++--- Sprint-1/fix/median.test.js | 2 +- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js index b22590bc6..73a1bf5d5 100644 --- a/Sprint-1/fix/median.js +++ b/Sprint-1/fix/median.js @@ -6,9 +6,23 @@ // 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; // Must be an array with atleast one elemnt + + const numbers = list.filter( + (x) => typeof x === "number" && Number.isFinite(x) + ); // filters out non-numeric values + + if (numbers.length === 0) return null; // Must have at least one number + + const sorted = [...numbers].sort((a, b) => a - b); + // numeric array copied before sorting in ascending order so that original array not mutated + + const mid = Math.floor(sorted.length / 2); // math.floor gives the correct index + if (sorted.length % 2 === 1) { + return sorted[mid]; // odd length; median is single centre value + } else { + return (sorted[mid - 1] + sorted[mid]) / 2; // even length; median is average of two centre values + } } module.exports = calculateMedian; diff --git a/Sprint-1/fix/median.test.js b/Sprint-1/fix/median.test.js index 21da654d7..66176b044 100644 --- a/Sprint-1/fix/median.test.js +++ b/Sprint-1/fix/median.test.js @@ -1,6 +1,6 @@ // median.test.js -// Someone has implemented calculateMedian but it isn't +// Someone has implemented calculateMedian but it isn't // passing all the tests... // Fix the implementation of calculateMedian so it passes all tests From ae016ef6f076150c34c71aca609d9141d580d660 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Sat, 15 Nov 2025 16:14:33 +0000 Subject: [PATCH 2/9] write and test findMax function to handle a variety of cases --- Sprint-1/implement/max.js | 16 ++++++++++++++++ Sprint-1/implement/max.test.js | 22 +++++++++++++++++++++- 2 files changed, 37 insertions(+), 1 deletion(-) diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js index 6dd76378e..6d810ee9d 100644 --- a/Sprint-1/implement/max.js +++ b/Sprint-1/implement/max.js @@ -1,4 +1,20 @@ function findMax(elements) { + if (!Array.isArray(elements) || elements.length === 0) { + return -Infinity; + } + const numbers = elements.filter( + (x) => typeof x === "number" && Number.isFinite(x) + ); + // Filters out all non-numeric values + if (numbers.length === 0) return -Infinity; + // Matches empty array behavior + let max = -Infinity; // All negative and positive numbers are greater than this minimum starting value + for (const n of numbers) { + // Loops through each n in array, if greater than max, assigns n to max + if (n > max) max = n; + } + return max; + } module.exports = findMax; diff --git a/Sprint-1/implement/max.test.js b/Sprint-1/implement/max.test.js index 82f18fd88..bba94b04c 100644 --- a/Sprint-1/implement/max.test.js +++ b/Sprint-1/implement/max.test.js @@ -16,28 +16,48 @@ 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("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("array with one number returns that number", () => { + expect(findMax([42])).toBe(42); +}); // Given an array with both positive and negative numbers // When passed to the max function // Then it should return the largest number overall +test("array with positive and negative numbers returns the largest number", () => { + expect(findMax([-10, 0, 5, 20, -3])).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("all negative numbers returns the closest to zero", () => { + expect(findMax([-50, -20, -3, -40])).toBe(-3); +}); // Given an array with decimal numbers // When passed to the max function // Then it should return the largest decimal number +test("array with decimal numbers returns the largest decimal", () => { + expect(findMax([1.5, 2.7, 0.3, 2.6])).toBe(2.7); +}); // 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("ignores non-number values and returns the max of numeric values", () => { + expect(findMax([10, "hello", 25, null, 15, undefined, 5])).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("array with only non-number values returns -Infinity", () => { + expect(findMax(["a", null, undefined, {}, []])).toBe(-Infinity); +}); From 49e91ddaeab86dc7f06b8b2f661c21874b08b35b Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Sun, 16 Nov 2025 12:29:13 +0000 Subject: [PATCH 3/9] sum function written and passes all tests --- Sprint-1/implement/sum.js | 14 ++++++++++++-- Sprint-1/implement/sum.test.js | 19 ++++++++++++++++++- 2 files changed, 30 insertions(+), 3 deletions(-) diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js index 9062aafe3..905bf0afb 100644 --- a/Sprint-1/implement/sum.js +++ b/Sprint-1/implement/sum.js @@ -1,4 +1,14 @@ -function sum(elements) { -} +function sum(arr) { + let total = 0; // variable keeps track of the sum + for (let element of arr) { + // iterate through each element in the array + if (typeof element === "number") { + // check if the element is a number + total += element; // add the number to the total sum + } + } + + return total; // return the final sum +} module.exports = sum; diff --git a/Sprint-1/implement/sum.test.js b/Sprint-1/implement/sum.test.js index dd0a090ca..8c413e45b 100644 --- a/Sprint-1/implement/sum.test.js +++ b/Sprint-1/implement/sum.test.js @@ -13,24 +13,41 @@ 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("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 one number, returns that number", () => { + expect(sum([42])).toBe(42); +}); // 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 with negative numbers, returns the correct sum", () => { + expect(sum([10, -5, 15, -10])).toBe(10); +}); // 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 the correct sum", () => { + expect(sum([1.5, 2.5, 3.0])).toBe(7.0); +}); // 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 the sum of numbers", () => { + expect(sum([10, "hello", 20, null, 30, undefined, "50"])).toBe(60); +}); // 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 an array with only non-number values, returns 0", () => { + expect(sum(["hello", null, undefined, "50"])).toBe(0); +}); From 83231429e053406012ee4f7fa7d58a09976b7c91 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Sun, 16 Nov 2025 12:48:43 +0000 Subject: [PATCH 4/9] dedupe function written and passing all tests --- Sprint-1/implement/dedupe.js | 15 ++++++++++++++- Sprint-1/implement/dedupe.test.js | 14 ++++++++++++-- 2 files changed, 26 insertions(+), 3 deletions(-) diff --git a/Sprint-1/implement/dedupe.js b/Sprint-1/implement/dedupe.js index 781e8718a..135b6a82a 100644 --- a/Sprint-1/implement/dedupe.js +++ b/Sprint-1/implement/dedupe.js @@ -1 +1,14 @@ -function dedupe() {} +function dedupe(arr) { + if (!Array.isArray(arr) || arr.length === 0) { + return []; + } + const result = []; // array to store unique elements + for (let element of arr) { + if (!result.includes(element)) { + // check if element is not already in result + result.push(element); // add unique element to result array + } + } + return result; +} +module.exports = dedupe; \ No newline at end of file diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js index 23e0f8638..3efb31508 100644 --- a/Sprint-1/implement/dedupe.test.js +++ b/Sprint-1/implement/dedupe.test.js @@ -16,12 +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("given an array with no duplicates, it returns the same array", () => { + expect(dedupe([1, 2, 3, 4, 5])).toEqual([1, 2, 3, 4, 5]); +}); // 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 +// Then it should remove the duplicate values, preserving the first occurrence of each element +test("given an array with duplicates, it removes the duplicates", () => { + expect(dedupe(['a', 'a', 'b', 'b', 'c'])).toEqual(['a', 'b', 'c']); + expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]); + expect(dedupe([1, 2, 1])).toEqual([1, 2]); +}); From c6076edb01e2e4617f857074ec1a05d387e77b10 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Sun, 16 Nov 2025 13:02:53 +0000 Subject: [PATCH 5/9] Refactored function to include a for...of loop --- Sprint-1/refactor/includes.js | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/Sprint-1/refactor/includes.js b/Sprint-1/refactor/includes.js index 29dad81f0..49b81b624 100644 --- a/Sprint-1/refactor/includes.js +++ b/Sprint-1/refactor/includes.js @@ -1,13 +1,14 @@ // 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 (let element of list) { + // iterate through each element in the list if (element === target) { - return true; + // check if the current element matches the target + return true; // return true if a match is found and exit the function } } - return false; + return false; // return false if no match is found after checking all elements } module.exports = includes; From 45d4be7781b5695e705cc5f76436bdd70f46a13d Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Fri, 5 Dec 2025 13:42:37 +0000 Subject: [PATCH 6/9] Refactor calculateMedian to eliminate unnecessary array cloning before sorting --- Sprint-1/fix/median.js | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Sprint-1/fix/median.js b/Sprint-1/fix/median.js index 73a1bf5d5..3caa319c7 100644 --- a/Sprint-1/fix/median.js +++ b/Sprint-1/fix/median.js @@ -14,8 +14,8 @@ function calculateMedian(list) { if (numbers.length === 0) return null; // Must have at least one number - const sorted = [...numbers].sort((a, b) => a - b); - // numeric array copied before sorting in ascending order so that original array not mutated + const sorted = numbers.slice().sort((a, b) => a - b); + // replaced unnecessary array clone const mid = Math.floor(sorted.length / 2); // math.floor gives the correct index if (sorted.length % 2 === 1) { From 8aae3f8351b014d06259df8e88d1e250a64f7fd3 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Fri, 5 Dec 2025 13:48:33 +0000 Subject: [PATCH 7/9] Refactor findMax to eliminate unnecessary array filtering --- Sprint-1/implement/max.js | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/Sprint-1/implement/max.js b/Sprint-1/implement/max.js index 6d810ee9d..fd23a60f8 100644 --- a/Sprint-1/implement/max.js +++ b/Sprint-1/implement/max.js @@ -2,18 +2,16 @@ function findMax(elements) { if (!Array.isArray(elements) || elements.length === 0) { return -Infinity; } - const numbers = elements.filter( - (x) => typeof x === "number" && Number.isFinite(x) - ); - // Filters out all non-numeric values - if (numbers.length === 0) return -Infinity; - // Matches empty array behavior - let max = -Infinity; // All negative and positive numbers are greater than this minimum starting value - for (const n of numbers) { - // Loops through each n in array, if greater than max, assigns n to max - if (n > max) max = n; - } - return max; + let max = -Infinity; + +for (const x of elements) { + if (typeof x === "number" && Number.isFinite(x)) { + if (x > max) max = x; + } +} + +return max; +// removed .filter as this creates a new array so this avoids unnecessary clones } From 214e4428a7ffffd039f6960f71239cd26f3515a3 Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Fri, 5 Dec 2025 13:50:00 +0000 Subject: [PATCH 8/9] Refactor sum function to use Number.isFinite for better number validation --- Sprint-1/implement/sum.js | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Sprint-1/implement/sum.js b/Sprint-1/implement/sum.js index 905bf0afb..b91c5b24a 100644 --- a/Sprint-1/implement/sum.js +++ b/Sprint-1/implement/sum.js @@ -3,8 +3,8 @@ function sum(arr) { for (let element of arr) { // iterate through each element in the array - if (typeof element === "number") { - // check if the element is a number + if (Number.isFinite(element)) { + // check if the element is a number, without counting NaN or Infinity total += element; // add the number to the total sum } } From eb7b89fb16caba3ec2e8cb7327f99519f093953b Mon Sep 17 00:00:00 2001 From: zilinskyte Date: Fri, 5 Dec 2025 13:58:18 +0000 Subject: [PATCH 9/9] Add test to ensure dedupe returns a new array reference --- Sprint-1/implement/dedupe.test.js | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/Sprint-1/implement/dedupe.test.js b/Sprint-1/implement/dedupe.test.js index 3efb31508..dabdfa23e 100644 --- a/Sprint-1/implement/dedupe.test.js +++ b/Sprint-1/implement/dedupe.test.js @@ -27,6 +27,14 @@ test("given an array with no duplicates, it returns the same array", () => { expect(dedupe([1, 2, 3, 4, 5])).toEqual([1, 2, 3, 4, 5]); }); +// When passed an array +// It should not return the same array reference +test("It returns a new array, not the original", () => { + const original = [1, 2, 3]; + const result = dedupe(original); + expect(result).not.toBe(original); // Check that the returned array is not the same reference as the original +}); + // Given an array with strings or numbers // When passed to the dedupe function // Then it should remove the duplicate values, preserving the first occurrence of each element