From d4df6a48c8b6f1720b5fbd06c2ce2d6511b872cb Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 26 Jul 2026 19:20:57 +0100
Subject: [PATCH 01/17] fix the problem

---
 Sprint-2/debug/address.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/debug/address.js b/Sprint-2/debug/address.js
index 940a6af83..500678113 100644
--- a/Sprint-2/debug/address.js
+++ b/Sprint-2/debug/address.js
@@ -12,4 +12,7 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address["houseNumber"]}`);
+// to access the houseNumber of the object using bracket notation,
+//  we need to use the key as a string. In this case, "houseNumber"
+//  is the correct key, so the code should work as expected.

From 9256b7f5bf8b60cc4f65bdceab3e80d26282a18a Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 13:11:03 +0100
Subject: [PATCH 02/17] debug the code

---
 Sprint-2/debug/author.js | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 8c2125977..88dee3e5a 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -3,13 +3,18 @@
 // 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
 
-const author = {
-  firstName: "Zadie",
-  lastName: "Smith",
-  occupation: "writer",
-  age: 40,
-  alive: true,
-};
+// I think the issue with the original code is it was trying to loop over the object directly,
+//  which is not iterable. Instead, we should loop over the array that contains the object.
+
+const author = [
+  {
+    firstName: "Zadie",
+    lastName: "Smith",
+    occupation: "writer",
+    age: 40,
+    alive: true,
+  },
+];
 
 for (const value of author) {
   console.log(value);

From 522cb564d58ec8f26c3482b8a0a18bf801288717 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 13:18:29 +0100
Subject: [PATCH 03/17] debug, and fix code

---
 Sprint-2/debug/recipe.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/debug/recipe.js b/Sprint-2/debug/recipe.js
index 6cbdd22cd..36cade6d0 100644
--- a/Sprint-2/debug/recipe.js
+++ b/Sprint-2/debug/recipe.js
@@ -12,4 +12,5 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
   ingredients:
-${recipe}`);
+${recipe.ingredients.join("\n")}`); //the DOT expression was missing in the original code.
+// also adding a join method to the ingredients array to log each ingredient on a new line.

From 5dcae6a49f6f6b33e9b9b4f80a1724424c5d9c6e Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 14:08:02 +0100
Subject: [PATCH 04/17] add two tests and implement function acordingly

---
 Sprint-2/implement/contains.js      | 4 +++-
 Sprint-2/implement/contains.test.js | 7 ++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index cd779308a..61ea51616 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,3 +1,5 @@
-function contains() {}
+function contains(obj, prop) {
+  return prop in obj; // checks if the property exists in the object and returns true or false
+}
 
 module.exports = contains;
diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 326bdb1f2..f8ea9e9e1 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -16,11 +16,16 @@ as the object doesn't contains a key of 'c'
 // Given a contains function
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
+test("contains an object returns true, or false otherwise", () => {
+  expect(contains({a: 1, b: 2, c: 3}, "a")).toBe(true);
+});
 
 // 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

From c68ec3e5df65687d5ee52d503a80740df2c74946 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 14:13:38 +0100
Subject: [PATCH 05/17] add more tests

---
 Sprint-2/implement/contains.test.js | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index f8ea9e9e1..9701b0d8b 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -16,9 +16,7 @@ as the object doesn't contains a key of 'c'
 // Given a contains function
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
-test("contains an object returns true, or false otherwise", () => {
-  expect(contains({a: 1, b: 2, c: 3}, "a")).toBe(true);
-});
+
 
 // Given an empty object
 // When passed to contains
@@ -30,11 +28,20 @@ test("contains on empty object returns false", () => {
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains an object returns true, or false otherwise", () => {
+  expect(contains({a: 1, b: 2, c: 3}, "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 an object returns true, or false otherwise", () => {
+  expect(contains({a: 1, b: 2, c: 3}, "d")).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("contains an object returns true, or false otherwise", () => {
+  expect(contains([1, 2, 3, 'a'], "a")).toBe(false);
+});

From bc5e89a67377d89a2ff249f0347b2b0aa7ec76e1 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 14:49:44 +0100
Subject: [PATCH 06/17] implement createLookup() function

---
 Sprint-2/implement/lookup.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/lookup.js b/Sprint-2/implement/lookup.js
index a6746e07f..95bd5e475 100644
--- a/Sprint-2/implement/lookup.js
+++ b/Sprint-2/implement/lookup.js
@@ -1,5 +1,6 @@
-function createLookup() {
-  // implementation here
+function createLookup(entries) {
+    let obj = Object.fromEntries(entries);
+    return obj;
 }
 
-module.exports = createLookup;
+module.exports = createLookup;
\ No newline at end of file

From 2114a9e3605ac10fcebcf9c7e9b1243cb78de05c Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 27 Jul 2026 16:08:46 +0100
Subject: [PATCH 07/17] write test

---
 Sprint-2/implement/lookup.test.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/implement/lookup.test.js b/Sprint-2/implement/lookup.test.js
index 547e06c5a..65d5878e0 100644
--- a/Sprint-2/implement/lookup.test.js
+++ b/Sprint-2/implement/lookup.test.js
@@ -1,6 +1,11 @@
 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", () => {
+  expect(createLookup([['US', 'USD'], ['CA', 'CAD']])).toEqual({
+    'US': 'USD',
+    'CA': 'CAD'
+  });
+});
 
 /*
 

From 78041d6228ba22ca5dc00f9d8c5f5038862cddfd Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 2 Aug 2026 18:24:17 +0100
Subject: [PATCH 08/17] write complete function to meet the test requirements

---
 Sprint-2/implement/querystring.js | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/querystring.js b/Sprint-2/implement/querystring.js
index 45ec4e5f3..ff2f0b4a5 100644
--- a/Sprint-2/implement/querystring.js
+++ b/Sprint-2/implement/querystring.js
@@ -3,11 +3,31 @@ function parseQueryString(queryString) {
   if (queryString.length === 0) {
     return queryParams;
   }
+  queryString = queryString.replace(/\+/g, " ");
   const keyValuePairs = queryString.split("&");
-
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    if (pair === "") {
+      continue;
+    }
+    let key;
+    let value;
+    const index = pair.indexOf("=");
+    if (index === -1) {
+      key = decodeURIComponent(pair);
+      value = "";
+    } else {
+      key = decodeURIComponent(pair.slice(0, index));
+      value = decodeURIComponent(pair.slice(index + 1));
+    }
+    if (!queryParams[key]) {
+      queryParams[key] = value;
+    } else {
+      if (Array.isArray(queryParams[key])) {
+        queryParams[key].push(value);
+      } else {
+        queryParams[key] = [queryParams[key], value];
+      }
+    }
   }
 
   return queryParams;

From 6d8eefd2c004e51889fc5668d0efb75e8db69e90 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 2 Aug 2026 21:35:42 +0100
Subject: [PATCH 09/17] write complete function to taly

---
 Sprint-2/implement/tally.js | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index f47321812..961c8ebe9 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -1,3 +1,20 @@
-function tally() {}
+function tally(arr) {
+  let countOfItemsObj = {};
+  if (!Array.isArray(arr)) {
+    throw new Error("Invalid input");
+  } else if (arr.length < 1) {
+    return countOfItemsObj;
+  } else {
+    for (let element = 0; element < arr.length; element++) {
+      const exist = Object.hasOwn(countOfItemsObj, arr[element]);
+      if (!exist) {
+        countOfItemsObj[arr[element]] = 1;
+      } else {
+        countOfItemsObj[arr[element]] = countOfItemsObj[arr[element]] + 1;
+      }
+    }
+  }
+  return countOfItemsObj;
+}
 
 module.exports = tally;

From fbce304baddac1cf73003eb50ca2910d4903b4b1 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 2 Aug 2026 21:38:15 +0100
Subject: [PATCH 10/17] wrte tests

---
 Sprint-2/implement/tally.test.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Sprint-2/implement/tally.test.js b/Sprint-2/implement/tally.test.js
index 2ceffa8dd..5284747d9 100644
--- a/Sprint-2/implement/tally.test.js
+++ b/Sprint-2/implement/tally.test.js
@@ -23,12 +23,20 @@ const tally = require("./tally.js");
 // 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 on an array with duplicate items returns counts for each unique item", () => {
+  expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+});
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally on an invalid input like a string throws an error", () => {
+  expect(() => tally("invalid input")).toThrow("Invalid input");
+});

From b10547d56264027c894a2227147fb43579f4e493 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Mon, 3 Aug 2026 10:20:13 +0100
Subject: [PATCH 11/17] fix function, write tests

---
 Sprint-2/interpret/invert.js | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/Sprint-2/interpret/invert.js b/Sprint-2/interpret/invert.js
index bb353fb1f..8cedb37da 100644
--- a/Sprint-2/interpret/invert.js
+++ b/Sprint-2/interpret/invert.js
@@ -10,20 +10,40 @@ 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 }
+// the current return value is { key: 1 }
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+// current return value is { key: 2 }
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+// the target return value is { "1": "a", "2": "b" }
 
 // c) What does Object.entries return? Why is it needed in this program?
+// Object.entries returns an array of key-value pairs from the object. It is needed 
+// in this program to iterate over each key-value pair in the object so that we can
+// swap them and create a new inverted object.
 
 // d) Explain why the current return value is different from the target output
+// I think current return value is different from the return value because the
+//  current implementation is not really swapping the properties of the object.
+//  Instead, it is just creating a new property called "key" and assigning the 
+// value to it. The target output requires us to swap the keys and values, which
+//  is not happening in the current implementation.
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)
+console.assert(
+  JSON.stringify(invert({ a: 1 })) === JSON.stringify({ "1": "a" }),
+  "Test 1 failed"
+);
+
+console.assert(
+  JSON.stringify(invert({ a: 1, b: 2 })) ===
+    JSON.stringify({ "1": "a", "2": "b" }),
+  "Test 2 failed"
+);

From 2dbe395b23f853e92edb18ad7aaea62479ef9e0b Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 14:05:10 +0100
Subject: [PATCH 12/17] Fix author iteration by using Object.entries

---
 Sprint-2/debug/author.js | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Sprint-2/debug/author.js b/Sprint-2/debug/author.js
index 88dee3e5a..8be7fc47f 100644
--- a/Sprint-2/debug/author.js
+++ b/Sprint-2/debug/author.js
@@ -6,16 +6,15 @@
 // I think the issue with the original code is it was trying to loop over the object directly,
 //  which is not iterable. Instead, we should loop over the array that contains the object.
 
-const author = [
+const author = 
   {
     firstName: "Zadie",
     lastName: "Smith",
     occupation: "writer",
     age: 40,
     alive: true,
-  },
-];
+  }
 
-for (const value of author) {
-  console.log(value);
+for (let [key, value] of Object.entries(author)) {
+    console.log(key, value);
 }

From 91bfc231a542eee24df8d5c9c3462802827e9396 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 15:20:15 +0100
Subject: [PATCH 13/17] Update property check to use hasOwnProperty

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

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index 61ea51616..a8d359816 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,5 +1,5 @@
 function contains(obj, prop) {
-  return prop in obj; // checks if the property exists in the object and returns true or false
+  return obj.hasOwnProperty(prop); // checks if the property exists in the object and returns true or false
 }
 
 module.exports = contains;

From aa5ee6806149252817d26802a72eee0e4baa854f Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 16:18:33 +0100
Subject: [PATCH 14/17] Update test case to check for array's indices

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

diff --git a/Sprint-2/implement/contains.test.js b/Sprint-2/implement/contains.test.js
index 9701b0d8b..ac93fea13 100644
--- a/Sprint-2/implement/contains.test.js
+++ b/Sprint-2/implement/contains.test.js
@@ -43,5 +43,5 @@ test("contains an object returns true, or false otherwise", () => {
 // When passed to contains
 // Then it should return false or throw an error
 test("contains an object returns true, or false otherwise", () => {
-  expect(contains([1, 2, 3, 'a'], "a")).toBe(false);
+  expect(contains([1, 2, 3, 'a'], "0")).toBe(false);
 });

From 4349ed1443ffa3e3e5e56ad0215cada0e9dde90b Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 16:20:25 +0100
Subject: [PATCH 15/17] Modify contains function to handle arrays

Add check for arrays in contains function
---
 Sprint-2/implement/contains.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index a8d359816..f38484cd5 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,5 +1,6 @@
 function contains(obj, prop) {
-  return obj.hasOwnProperty(prop); // checks if the property exists in the object and returns true or false
+    if (Array.isArray(obj)) {
+        return false; // returns false if an object contains an array
+    }
+  return obj.hasOwnProperty(prop);
 }
-
-module.exports = contains;

From aff50e0c64b9f04404ea29a73c1a5f39f8dcc17d Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 16:47:14 +0100
Subject: [PATCH 16/17] Fix loop index variable in tally function

---
 Sprint-2/implement/tally.js | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Sprint-2/implement/tally.js b/Sprint-2/implement/tally.js
index 961c8ebe9..0cee81429 100644
--- a/Sprint-2/implement/tally.js
+++ b/Sprint-2/implement/tally.js
@@ -5,16 +5,15 @@ function tally(arr) {
   } else if (arr.length < 1) {
     return countOfItemsObj;
   } else {
-    for (let element = 0; element < arr.length; element++) {
-      const exist = Object.hasOwn(countOfItemsObj, arr[element]);
+    for (let index = 0; index < arr.length; index++) {
+      const exist = Object.hasOwn(countOfItemsObj, arr [index]);
       if (!exist) {
-        countOfItemsObj[arr[element]] = 1;
+        countOfItemsObj[arr[index]] = 1;
       } else {
-        countOfItemsObj[arr[element]] = countOfItemsObj[arr[element]] + 1;
+        countOfItemsObj[arr[index]] = countOfItemsObj[arr[index]] + 1;
       }
     }
   }
   return countOfItemsObj;
 }
-
 module.exports = tally;

From 9ca3f78279f62d5090173125c0363bd9ec3ae600 Mon Sep 17 00:00:00 2001
From: vmoratti <vmoratti@gmail.com>
Date: Sun, 9 Aug 2026 23:33:58 +0100
Subject: [PATCH 17/17] Improve contains function property check

Refactor contains function to handle null, undefined, and Number types.
---
 Sprint-2/implement/contains.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Sprint-2/implement/contains.js b/Sprint-2/implement/contains.js
index f38484cd5..99d4dfe98 100644
--- a/Sprint-2/implement/contains.js
+++ b/Sprint-2/implement/contains.js
@@ -1,6 +1,7 @@
 function contains(obj, prop) {
-    if (Array.isArray(obj)) {
-        return false; // returns false if an object contains an array
-    }
+    const notArray = !Array.isArray(obj);
+    if (obj === null || Array.isArray(obj) || obj === Number || obj === undefined) {
+        return false; 
+    }  
   return obj.hasOwnProperty(prop);
 }