From 7f411c4964d2793c670bce6771baf034a875a50f Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Tue, 7 Oct 2025 16:20:55 +0100
Subject: [PATCH 01/17] question answered and code fixed

---
 Sprint-2/debug/address.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/debug/address.js b/Sprint-2/debug/address.js
index 940a6af83..7236aa64a 100644
--- a/Sprint-2/debug/address.js
+++ b/Sprint-2/debug/address.js
@@ -1,4 +1,8 @@
 // Predict and explain first...
+/* address[0] does not access the houseNumber property of the address object. In JavaScript, objects are 
+accessed using their property names, not numerical indices. Therefore, address[0] is undefined because 
+there is no property with the key '0' in the address object. To access the houseNumber property, we should 
+use address.houseNumber or address['houseNumber']. */
 
 // This code should log out the houseNumber from the address object
 // but it isn't working...
@@ -12,4 +16,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address.houseNumber}`);

From 3bd2fa840e4337cb5f0db02082da970fef8ac31b Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Tue, 7 Oct 2025 16:44:26 +0100
Subject: [PATCH 02/17] question answered and code fixed

---
 Sprint-2/debug/author.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 8c2125977..6e61e0641 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -1,4 +1,8 @@
 // Predict and explain first...
+/* In JavaScript, objects are not iterable by default, which means you cannot use a for...of loop directly on an object. 
+The for...of loop is designed to work with iterable objects like arrays, strings, maps, and sets. Since the 'author' object 
+is not iterable, attempting to use for...of on it will result in a TypeError. To iterate over the properties of an object, 
+we can use Object.keys(), Object.values(), or Object.entries().*/
 
 // This program attempts to log out all the property values in the object.
 // But it isn't working. Explain why first and then fix the problem
@@ -11,6 +15,6 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+for (const value of Object.values(author)) {
   console.log(value);
 }

From 6f677424b048ab1a70760aaacf521b51b6d42d7c Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Tue, 7 Oct 2025 16:55:59 +0100
Subject: [PATCH 03/17] question answered and code fixed to log ingredients

---
 Sprint-2/debug/recipe.js | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index 6cbdd22cd..d0aed33c6 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -1,4 +1,8 @@
 // Predict and explain first...
+/* In JavaScript, when you try to log an object directly within a template literal, it doesn't automatically
+format the object in a readable way. Instead, it converts the object to a string, which results in "[object Object]".
+To properly display the ingredients on new lines, we need to join the array elements into a single string with 
+newline characters in between.*/
 
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
@@ -11,5 +15,8 @@ const recipe = {
 };
 
 console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+Ingredients:
+${recipe.ingredients.map(ingredients => `-${ingredients}`).join("\n")}`);
+// Using map to format each ingredient and join to create a single string with new lines 
+// between each ingredient.
+

From e384e28a1d30123a878c8ac12ce87275d23356f6 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Tue, 28 Oct 2025 11:05:18 +0000
Subject: [PATCH 04/17] updates

---
 Sprint-2/implement/contains.js      | 14 +++++++++++++-
 Sprint-2/implement/contains.test.js | 10 +++++++++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..2d4124ccb 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,15 @@
-function contains() {}
+function contains(obj, key) {
+  /**
+   * Checks if the given array contains the specified value.
+   * @param {Array} arr - The array to check.
+   * @param {*} value - The value to search for.
+   * @returns {boolean} - Returns true if the value is found, otherwise false.
+   */
+  if (obj === null || typeof obj !== "object" || Array.isArray(obj)) {
+    throw new TypeError("First argument must be a non-null object");
+  }
+
+  return Object.prototype.hasOwnProperty.call(obj, key);
+}
 
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..ce917ea0a 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -20,15 +20,23 @@ as the object doesn't contains a key of 'c'
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("contains on empty object returns false", () => {
+  expect(contains({}, "a")).toBe(false);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains on object with existing property returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains on object with non-existent property returns false", () => {
+  expect(contains({ a: 1, b: 2 }, "c")).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains

From 5aeb9476350387cdfe45caa1d77691b68f3cc2ca Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 30 Oct 2025 10:38:26 +0000
Subject: [PATCH 05/17] function fixed with test-cases

---
 Sprint-2/implement/contains.js      | 3 ++-
 Sprint-2/implement/contains.test.js | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index 2d4124ccb..e354f632f 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -6,10 +6,11 @@ function contains(obj, key) {
    * @returns {boolean} - Returns true if the value is found, otherwise false.
    */
   if (obj === null || typeof obj !== "object" || Array.isArray(obj)) {
-    throw new TypeError("First argument must be a non-null object");
+    return false;
   }
 
   return Object.prototype.hasOwnProperty.call(obj, key);
 }
 
 module.exports = contains;
+
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index ce917ea0a..d7cb15dcb 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -41,3 +41,8 @@ test("contains on object with non-existent property returns false", () => {
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("contains on invalid parameters returns false", () => {
+  expect(contains([], "a")).toBe(false);
+  expect(contains(null, "a")).toBe(false);
+  expect(contains(undefined, "a")).toBe(false);
+});

From 97a9291a39230ef514b567a3778be085a8ace468 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 30 Oct 2025 10:47:55 +0000
Subject: [PATCH 06/17] created function and testcases for lookups

---
 Sprint-2/implement/lookup.js      | 16 ++++++++++++++--
 Sprint-2/implement/lookup.test.js | 16 ++++++++++++++--
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..4d0442bdf 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,17 @@
-function createLookup() {
-  // implementation here
+function createLookup(pairs) {
+  /**
+   * Creates a lookup object from an array of [key, value] pairs.
+   * @param {Array<Array<string>>} pairs - An array of [countryCode, currencyCode] pairs.
+   * @returns {Object} - A lookup object mapping country codes to currency codes.
+   */
+  if (!Array.isArray(pairs)) {
+    throw new TypeError("Argument must be an array of pairs");
+  }
+
+  return pairs.reduce((lookup, [country, currency]) => {
+    lookup[country] = currency;
+    return lookup;
+  }, {});
 }
 
 module.exports = createLookup;
diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..d60bcd832 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,7 +1,19 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
+test("creates a country currency code lookup for multiple codes", () => {
+  const input = [
+    ["US", "USD"],
+    ["CA", "CAD"],
+    ["JP", "JPY"],
+  ];
+  const expected = {
+    US: "USD",
+    CA: "CAD",
+    JP: "JPY",
+  };
+
+  expect(createLookup(input)).toEqual(expected);
+});
 /*
 
 Create a lookup object of key value pairs from an array of code pairs

From c7188a01e48d5b3aa06be67ff54161525ef910eb Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 30 Oct 2025 10:56:14 +0000
Subject: [PATCH 07/17] fixed function to work with all the test-cases in
 querystring

---
 Sprint-2/implement/querystring.js      | 14 ++++++--
 Sprint-2/implement/querystring.test.js | 48 ++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..120cc2172 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -1,13 +1,21 @@
 function parseQueryString(queryString) {
   const queryParams = {};
-  if (queryString.length === 0) {
+  if (!queryString || queryString.length === 0) {
     return queryParams;
   }
+
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    if (!pair) continue; // skip empty entries (e.g. trailing &)
+    const [key, ...rest] = pair.split("=");
+    const value = rest.length > 0 ? rest.join("=") : null;
+
+    // Decode URI components
+    const decodedKey = decodeURIComponent(key);
+    const decodedValue = value === null ? null : decodeURIComponent(value);
+
+    queryParams[decodedKey] = decodedValue;
   }
 
   return queryParams;
diff --git a/Sprint-2/implement/querystring.test.js b/Sprint-2/implement/querystring.test.js
index 3e218b789..cd675b06b 100644
--- a/Sprint-2/implement/querystring.test.js
+++ b/Sprint-2/implement/querystring.test.js
@@ -10,3 +10,51 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+// Additional test cases to cover more edge cases
+// query strings with multiple key-value pairs
+test("parses querystring with multiple & and =", () => {
+  expect(parseQueryString("a=1&b=2&c=3")).toEqual({
+    "a": "1",
+    "b": "2",
+    "c": "3",
+  });
+});
+
+// query strings with empty keys
+test("parses querystring with empty value", () => {
+  expect(parseQueryString("key=")).toEqual({
+    "key": "",
+  });
+});
+
+// query strings with no value
+test("parses querystring with no value", () => {
+  expect(parseQueryString("flag")).toEqual({
+    "flag": null,
+  });
+});
+
+// query strings with encoded characters
+test("parses querystring with encoded characters", () => {
+  expect(parseQueryString("name=John%20Doe&city=New%20York")).toEqual({
+    "name": "John Doe",
+    "city": "New York",
+  });
+});
+
+// query strings with repeated keys
+test("parses querystring with repeated keys", () => {
+  expect(parseQueryString("key=1&key=2")).toEqual({
+    "key": "2", // assuming last value wins
+  });
+});
+
+// query strings with trailing &
+test("parses querystring with trailing &", () => {
+  expect(parseQueryString("key1=value1&key2=value2&")).toEqual({
+    "key1": "value1",
+    "key2": "value2",
+  });
+});
+

From e90d9dd16de5d68acaa6609b0559c94a44db80d1 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 30 Oct 2025 11:00:59 +0000
Subject: [PATCH 08/17] fixed function and added test-cases for tally

---
 Sprint-2/implement/tally.js      | 17 ++++++++++++++++-
 Sprint-2/implement/tally.test.js | 16 +++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..434c32cac 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,18 @@
-function tally() {}
+function tally(items) {
+  if (!Array.isArray(items)) {
+    throw new Error("Input must be an array");
+  }
 
+  const result = {};
+
+  for (const item of items) {
+    if (result[item]) {
+      result[item]++;
+    } else {
+      result[item] = 1;
+    }
+  }
+
+  return result;
+}
 module.exports = tally;
diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..1bc673eea 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -20,15 +20,29 @@ const tally = require("./tally.js");
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
 
+test("tally counts unique items in an array", () => {
+  expect(tally(["a"])).toEqual({ a: 1 });
+  expect(tally(["a", "a", "a"])).toEqual({ a: 3 });
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+});
+
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+test("tally on an empty array returns an empty object", () => {
+  expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("tally counts duplicates correctly", () => {
+  expect(tally(["apple", "banana", "apple"])).toEqual({ apple: 2, banana: 1 });
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally throws error for non-array input", () => {
+  expect(() => tally("not an array")).toThrow("Input must be an array");
+});

From 01d2170e4d709fadb6fafa521818b4c250c0e4cc Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 30 Oct 2025 11:17:15 +0000
Subject: [PATCH 09/17] function fixed and testcases created and tested to
 pass.

---
 Sprint-2/interpret/invert.js       | 16 +++++++++++++++-
 Sprint-2/interpret/inverts.test.js | 26 ++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 Sprint-2/interpret/inverts.test.js

diff --git a/Sprint-2/interpret/invert.js b/Sprint-2/interpret/invert.js
index bb353fb1f..a3ea0d144 100644
--- a/Sprint-2/interpret/invert.js
+++ b/Sprint-2/interpret/invert.js
@@ -10,20 +10,34 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
 
 // a) What is the current return value when invert is called with { a : 1 }
+// a) Current return value: { key: 1 }
+// a) Target return value: { 1: "a" }
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+// b) Current return value: { key: 2 }
+// b) Target return value: { 1: "a", 2: "b" }
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+// c) Current return value: { key: 2 }
+// c) Target return value: { 1: "a", 2: "b" }
 
 // c) What does Object.entries return? Why is it needed in this program?
+// c) Object.entries returns an array of a given object's own enumerable string-keyed property [key, value] pairs.
+// c) It is needed in this program to iterate over each key-value pair in the input object so that we can swap them and build the inverted object.
 
 // d) Explain why the current return value is different from the target output
+// d) The current return value is different from the target output because the implementation incorrectly assigns the value to a fixed key 'key' 
+// in the inverted object, rather than using the actual value from the original object as the key in the inverted object. This results in only the 
+// last processed value being stored under the same key 'key', overwriting any previous entries.
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+// e) Fixed implementation is provided above. Below are the test cases in a separate file.
+
+module.exports = invert;
\ No newline at end of file
diff --git a/Sprint-2/interpret/inverts.test.js b/Sprint-2/interpret/inverts.test.js
new file mode 100644
index 000000000..a120bcc59
--- /dev/null
+++ b/Sprint-2/interpret/inverts.test.js
@@ -0,0 +1,26 @@
+const invert = require("./invert");
+
+// Test cases for single key-value pair
+test("inverts a single key-value pair", () => {
+  expect(invert({ a: 1 })).toEqual({ 1: "a" });
+});
+
+// Test cases for multiple key-value pairs
+test("inverts multiple key-value pairs", () => {
+  expect(invert({ a: 1, b: 2 })).toEqual({ 1: "a", 2: "b" });
+});
+
+// Test cases for string values
+test("inverts string values", () => {
+  expect(invert({ a: "x", b: "y" })).toEqual({ x: "a", y: "b" });
+});
+
+// Test cases for mixed value types
+test("overwrites keys when values are not unique", () => {
+  expect(invert({ a: 1, b: 1 })).toEqual({ 1: "b" }); // last one wins
+});
+
+// Test cases for empty object
+test("inverts an empty object", () => {
+  expect(invert({})).toEqual({});
+});

From 8aee17ec34671a25b196236efc7e9af24c47892f Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Sun, 16 Nov 2025 10:49:55 +0000
Subject: [PATCH 10/17] element name fixed

---
 Sprint-2/debug/recipe.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index d0aed33c6..324a827fa 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -16,7 +16,7 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
 Ingredients:
-${recipe.ingredients.map(ingredients => `-${ingredients}`).join("\n")}`);
+${recipe.ingredients.map(ingredient => `-${ingredient}`).join("\n")}`);
 // Using map to format each ingredient and join to create a single string with new lines 
 // between each ingredient.
 

From c8e50b387fcab3fc07c56d77e87105b5b3523467 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Sun, 16 Nov 2025 11:05:07 +0000
Subject: [PATCH 11/17] contains-test fixed

---
 Sprint-2/implement/contains.test.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index d7cb15dcb..94e9dd96f 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -21,7 +21,9 @@ as the object doesn't contains a key of 'c'
 // When passed to contains
 // Then it should return false
 test("contains on empty object returns false", () => {
-  expect(contains({}, "a")).toBe(false);
+  expect(contains(null, "a")).toBe(false);
+  expect(contains(123, "a")).toBe(false);
+  expect(contains("not array", "a")).toBe(false);
 });
 
 // Given an object with properties

From 9d158ec59bfd09284c4b1f3402b0ed3fcfb1a4ca Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Wed, 19 Nov 2025 11:19:09 +0000
Subject: [PATCH 12/17] fixed contains function and contains-test

---
 Sprint-2/implement/contains.js      | 10 ++---
 Sprint-2/implement/contains.test.js | 63 +++++++++++++++--------------
 2 files changed, 36 insertions(+), 37 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index e354f632f..634912f7d 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,16 +1,12 @@
-function contains(obj, key) {
+function contains(arr, value) {
   /**
    * Checks if the given array contains the specified value.
    * @param {Array} arr - The array to check.
    * @param {*} value - The value to search for.
    * @returns {boolean} - Returns true if the value is found, otherwise false.
    */
-  if (obj === null || typeof obj !== "object" || Array.isArray(obj)) {
-    return false;
-  }
-
-  return Object.prototype.hasOwnProperty.call(obj, key);
+  if (!Array.isArray(arr)) return false;
+  return arr.includes(value);
 }
 
 module.exports = contains;
-
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 94e9dd96f..146d145de 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -17,34 +17,37 @@ as the object doesn't contains a key of 'c'
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
 
-// Given an empty object
-// When passed to contains
-// Then it should return false
-test("contains on empty object returns false", () => {
-  expect(contains(null, "a")).toBe(false);
-  expect(contains(123, "a")).toBe(false);
-  expect(contains("not array", "a")).toBe(false);
-});
-
-// Given an object with properties
-// When passed to contains with an existing property name
-// Then it should return true
-test("contains on object with existing property returns true", () => {
-  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
-});
-
-// Given an object with properties
-// When passed to contains with a non-existent property name
-// Then it should return false
-test("contains on object with non-existent property returns false", () => {
-  expect(contains({ a: 1, b: 2 }, "c")).toBe(false);
-});
-
-// Given invalid parameters like an array
-// When passed to contains
-// Then it should return false or throw an error
-test("contains on invalid parameters returns false", () => {
-  expect(contains([], "a")).toBe(false);
-  expect(contains(null, "a")).toBe(false);
-  expect(contains(undefined, "a")).toBe(false);
+describe("contains (array-only version)", () => {
+  // Given an empty object
+  // When passed to contains
+  // Then it should return false
+  test("returns false for an empty object", () => {
+    expect(contains({}, "anything")).toBe(false);
+  });
+
+  // Given an object with properties
+  // When passed to contains with an existing property name
+  // Then it should return false
+  test("returns false even if object has that property", () => {
+    expect(contains({ a: 1, b: 2 }, "a")).toBe(false);
+  });
+
+  // Given an object with properties
+  // When passed to contains with a non-existent property name
+  // Then it should return false
+  test("returns false for non-existent key on object", () => {
+    expect(contains({ a: 1, b: 2 }, "z")).toBe(false);
+  });
+
+  // Given invalid parameters like an array
+  // When passed to contains
+  // Then it should return false or throw an error
+  test("returns false for invalid inputs", () => {
+    expect(contains(null, "a")).toBe(false);
+    expect(contains(undefined, "a")).toBe(false);
+    expect(contains(123, "a")).toBe(false);
+    expect(contains("string", "s")).toBe(false);
+    expect(contains(true, true)).toBe(false);
+  });
 });
+// Note: The contains function implemented in contains.js only works for arrays.
\ No newline at end of file

From 83214e4a6db68c95e2862755011db329dba46063 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Wed, 19 Nov 2025 11:31:57 +0000
Subject: [PATCH 13/17] fixed prototype issue

---
 Sprint-2/implement/tally.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index 434c32cac..80f6bf5f5 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -3,7 +3,7 @@ function tally(items) {
     throw new Error("Input must be an array");
   }
 
-  const result = {};
+  const result = Object.create(null); // Create a clean object with no prototype
 
   for (const item of items) {
     if (result[item]) {

From 5cf0ffbad72fb32e41c75d17ae39bc6407dc9a58 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Wed, 19 Nov 2025 11:50:01 +0000
Subject: [PATCH 14/17] changed parameter

---
 Sprint-2/implement/contains.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index 634912f7d..6b5c6a99d 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,12 +1,12 @@
-function contains(arr, value) {
+function contains(arr, item) {
   /**
    * Checks if the given array contains the specified value.
    * @param {Array} arr - The array to check.
-   * @param {*} value - The value to search for.
+   * @param {*} item - The item to search for.
    * @returns {boolean} - Returns true if the value is found, otherwise false.
    */
   if (!Array.isArray(arr)) return false;
-  return arr.includes(value);
+  return arr.includes(item);
 }
 
 module.exports = contains;

From 295d8fa34a4542b56e35e7958826aeb18c666e93 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Wed, 19 Nov 2025 12:42:57 +0000
Subject: [PATCH 15/17] chnaged the contains function

---
 Sprint-2/implement/contains.js      | 22 ++++++----
 Sprint-2/implement/contains.test.js | 65 ++++++++++++++---------------
 2 files changed, 45 insertions(+), 42 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index 6b5c6a99d..f02d93a97 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,12 +1,16 @@
-function contains(arr, item) {
-  /**
-   * Checks if the given array contains the specified value.
-   * @param {Array} arr - The array to check.
-   * @param {*} item - The item to search for.
-   * @returns {boolean} - Returns true if the value is found, otherwise false.
-   */
-  if (!Array.isArray(arr)) return false;
-  return arr.includes(item);
+// function that checks if a given property exists in an object
+function contains(obj, property) {
+  // Check if the input is a valid object and not null or an array
+  if (
+    typeof obj === "object" &&
+    obj !== null &&
+    !Array.isArray(obj) &&
+    property in obj
+  ) {
+    return true;
+  } else {
+    return false;
+  }
 }
 
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 146d145de..c3ed0cd2e 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -17,37 +17,36 @@ as the object doesn't contains a key of 'c'
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
 
-describe("contains (array-only version)", () => {
-  // Given an empty object
-  // When passed to contains
-  // Then it should return false
-  test("returns false for an empty object", () => {
-    expect(contains({}, "anything")).toBe(false);
-  });
-
-  // Given an object with properties
-  // When passed to contains with an existing property name
-  // Then it should return false
-  test("returns false even if object has that property", () => {
-    expect(contains({ a: 1, b: 2 }, "a")).toBe(false);
-  });
-
-  // Given an object with properties
-  // When passed to contains with a non-existent property name
-  // Then it should return false
-  test("returns false for non-existent key on object", () => {
-    expect(contains({ a: 1, b: 2 }, "z")).toBe(false);
-  });
-
-  // Given invalid parameters like an array
-  // When passed to contains
-  // Then it should return false or throw an error
-  test("returns false for invalid inputs", () => {
-    expect(contains(null, "a")).toBe(false);
-    expect(contains(undefined, "a")).toBe(false);
-    expect(contains(123, "a")).toBe(false);
-    expect(contains("string", "s")).toBe(false);
-    expect(contains(true, true)).toBe(false);
-  });
+// When passed an empty object
+// Then it should return false
+test("contains on empty object returns false", () => {
+  const emptyObject = {};
+  expect(contains(emptyObject, "key")).toBe(false);
 });
-// Note: The contains function implemented in contains.js only works for arrays.
\ No newline at end of file
+
+// When passed a non-object value (e.g., array, string, number, null, undefined)
+// Then it should return false
+test("Checks if an object contains the specified property", () => {
+  const obj1 = { name: "Alice", age: 30 };
+  expect(contains(obj1, "name")).toBe(true); // The property "name" exists
+  expect(contains(obj1, "city")).toBe(false); // The property "city" does not exist
+});
+
+// contains({ a: 1, b: 2 }, 'a') // returns true
+test("Checks if an object contains the specified property", () => {
+  const obj1 = { a: 1, b: 2 };
+  expect(contains(obj1, "a")).toBe(true); // The property "name" exists
+});
+
+// contains({ a: 1, b: 2 }, 'c') // returns false
+test("Checks if an object contains the specified property", () => {
+  const obj1 = { a: 1, b: 2 };
+  expect(contains(obj1, "c")).toBe(false); // The property "c" does not exist
+});
+
+// when given an array instead of an object returns false
+test(" when given an array instead of an object returns false", () => {
+  const arrayInput = ["value1", "value2"];
+  expect(contains(arrayInput, "key")).toBe(false); // The property "key" does not exist
+});
+

From 5d258821900ea022fba435eb008b51a8cd5addff Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 20 Nov 2025 10:05:41 +0000
Subject: [PATCH 16/17] fixed

---
 Sprint-2/implement/contains.js      | 4 ++--
 Sprint-2/implement/contains.test.js | 8 ++------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index f02d93a97..780befb78 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -5,8 +5,8 @@ function contains(obj, property) {
     typeof obj === "object" &&
     obj !== null &&
     !Array.isArray(obj) &&
-    property in obj
-  ) {
+    Object.hasOwn(obj, property
+  )) {
     return true;
   } else {
     return false;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index c3ed0cd2e..3d9042cee 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -32,18 +32,14 @@ test("Checks if an object contains the specified property", () => {
   expect(contains(obj1, "city")).toBe(false); // The property "city" does not exist
 });
 
-// contains({ a: 1, b: 2 }, 'a') // returns true
+// contains({ a: 1, b: 2 }, 'a') // returns true and contains({ a: 1, b: 2 }, 'c') // returns false
 test("Checks if an object contains the specified property", () => {
   const obj1 = { a: 1, b: 2 };
   expect(contains(obj1, "a")).toBe(true); // The property "name" exists
-});
-
-// contains({ a: 1, b: 2 }, 'c') // returns false
-test("Checks if an object contains the specified property", () => {
-  const obj1 = { a: 1, b: 2 };
   expect(contains(obj1, "c")).toBe(false); // The property "c" does not exist
 });
 
+
 // when given an array instead of an object returns false
 test(" when given an array instead of an object returns false", () => {
   const arrayInput = ["value1", "value2"];

From 131159ad1e6d1402c1a4315213e520fa120eaf47 Mon Sep 17 00:00:00 2001
From: AdnaanA <thetriplex247@gmail.com>
Date: Thu, 20 Nov 2025 10:06:12 +0000
Subject: [PATCH 17/17] updated

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

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index 780befb78..0cfd61835 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -5,8 +5,8 @@ function contains(obj, property) {
     typeof obj === "object" &&
     obj !== null &&
     !Array.isArray(obj) &&
-    Object.hasOwn(obj, property
-  )) {
+    Object.hasOwn(obj, property)
+  ) {
     return true;
   } else {
     return false;