London | 25-ITP-Sept | Samuel Tarawally | Sprint 1 | Coursework

.gitignore

@@ -1,4 +1,39 @@
-node_modules
+# Generated .gitignore file for: Node, JavaScript
+# Created with FOSSA's DevOps Tools
+
+# Node
+node_modules/
+npm-debug.log
+yarn-error.log
+.env
 .DS_Store
-.vscode
-**/.DS_Store
+dist/
+.cache/
+coverage/
+
+# JavaScript
+# Add JavaScript-specific ignores here
+package-lock.json
+
+# Notebooks and documentation
+docs/
+
+# Common
+.DS_Store
+Thumbs.db
+*.log
+*.bak
+*.tmp
+*.swp
+*~
+
+# IDE and editor generated files
+.idea/
+*.sublime-*
+.vscode/
+.devcontainer/
+
+# Local environment files
+.env
+.env.local
+.env.*.local

Sprint-1/1-key-exercises/1-count.js

@@ -4,3 +4,6 @@ count = count + 1;
 
 // Line 1 is a variable declaration, creating the count variable with an initial value of 0
 // Describe what line 3 is doing, in particular focus on what = is doing
+
+// Line 3 reassigns the count variable by evaluating the expression on the right hand side of the assignment.
+// The right hand side (count + 1) is evaluated first, then the = operator assigns that value to count.

Sprint-1/1-key-exercises/2-initials.js

@@ -5,7 +5,5 @@ let lastName = "Johnson";
 // Declare a variable called initials that stores the first character of each string.
 // This should produce the string "CKJ", but you must not write the characters C, K, or J in the code of your solution.
 
-let initials = ``;
-
-// https://www.google.com/search?q=get+first+character+of+string+mdn
-
+let initials = `${firstName[0]}${middleName[0]}${lastName[0]}`;
+console.log(initials);

Sprint-1/1-key-exercises/3-paths.js

@@ -17,7 +17,7 @@ console.log(`The base part of ${filePath} is ${base}`);
 // Create a variable to store the dir part of the filePath variable
 // Create a variable to store the ext part of the variable
 
-const dir = ;
-const ext = ;
+const dir = filePath.slice(0, lastSlashIndex + 1);
+const ext = base.slice(base.lastIndexOf("."));
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

Sprint-1/1-key-exercises/4-random.js

@@ -3,7 +3,37 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
-// In this exercise, you will need to work out what num represents?
-// Try breaking down the expression and using documentation to explain what it means
-// It will help to think about the order in which expressions are evaluated
-// Try logging the value of num and running the program several times to build an idea of what the program is doing
+// Breakdown of the 'num' declaration
+// The expression of `num` can be broken down into several discrete steps:
+
+// 1. `Math.random()`, this generates a random floating point number
+// This number is between 0 (inclusive) and 1 (exclusive)
+console.log("Math.random():", Math.random());
+
+// 2. `(maximum - minimum + 1)` this part simple resolve to 100
+console.log("maximum - minimum + 1:", maximum - minimum + 1);
+
+// 3. By multiplying steps 1 and 2, the floating point number is scaled from 0-1 to 0-100
+// This adjusted scale is defined by the `minimum` and `maximum` variables declared earlier
+console.log(
+  "Math.random() * (maximum - minimum + 1):",
+  Math.random() * (maximum - minimum + 1)
+);
+
+// 4. `Math.floor()` then rounds down to the nearest whole number
+// Turning the floating point number into a whole number and adjusting the range from 0-99
+console.log(
+  "Math.floor(Math.random() * (maximum - minimum + 1)):",
+  Math.floor(Math.random() * (maximum - minimum + 1))
+);
+
+// 5. Lastly, `+ minimum` shifts the result up by the value of 1
+// In effect, this adjusts the range from 0-99 to 1-100
+console.log(
+  "Math.floor(Math.random() * (maximum - minimum + 1)) + minimum:",
+  Math.floor(Math.random() * (maximum - minimum + 1)) + minimum
+);
+
+// The final result is a random whole number between minimum (1) and maximum (100)
+// Where 100 is an inclusive valid value in the range
+console.log("num:", num);

Sprint-1/2-mandatory-errors/0.js

@@ -1,2 +1,6 @@
-This is just an instruction for the first activity - but it is just for human consumption
-We don't want the computer to run these 2 lines - how can we solve this problem?
+// This is just an instruction for the first activity - but it is just for human consumption
+// We don't want the computer to run these 2 lines - how can we solve this problem?
+
+// Answer: Use comments (//) to prevent execution
+// SyntaxError: Unexpected identifier - plain text is not valid JavaScript
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#comments

Sprint-1/2-mandatory-errors/1.js

@@ -1,4 +1,11 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+// const age = 33;
+// age = age + 1;
+
+// TypeError: Assignment to constant variable - `const` cannot be reassigned
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const
+
+// Solution:
+let age = 33;
 age = age + 1;

Sprint-1/2-mandatory-errors/2.js

@@ -1,5 +1,12 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
-// what's the error ?
+// What's the error?
 
-console.log(`I was born in ${cityOfBirth}`);
+// console.log(`I was born in ${cityOfBirth}`);
+// const cityOfBirth = "Bolton";
+
+// ReferenceError: Cannot access 'cityOfBirth' before initialization - temporal dead zone
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const#temporal_dead_zone_tdz
+
+// Solution:
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

Sprint-1/2-mandatory-errors/3.js

@@ -1,9 +1,16 @@
-const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+// const cardNumber = 4533787178994213;
+// const last4Digits = cardNumber.slice(-4);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
 // Before running the code, make and explain a prediction about why the code won't work
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+
+// TypeError: cardNumber.slice is not a function - .slice() exists on strings, not numbers
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/slice
+
+// Solution:
+const cardNumber = 4533787178994213;
+const last4Digits = String(cardNumber).slice(-4);

Sprint-1/2-mandatory-errors/4.js

@@ -1,2 +1,9 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+// const 12HourClockTime = "20:53";
+// const 24hourClockTime = "08:53";
+
+// SyntaxError: Invalid or unexpected token - variable names cannot start with a digit
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Grammar_and_types#variables
+
+// Solution:
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -12,11 +12,20 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+// 6 function calls: Line 4 (replaceAll, Number), Line 5 (replaceAll, Number), Line 10 (console.log)
 
 // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
+// SyntaxError on line 5: missing comma between arguments "," and ""
+// Fix: priceAfterOneYear.replaceAll(",", "")
 
 // c) Identify all the lines that are variable reassignment statements
+// Line 4: carPrice = Number(carPrice.replaceAll(",", ""));
+// Line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // d) Identify all the lines that are variable declarations
+// Line 1: let carPrice, Line 2: let priceAfterOneYear, Line 7: const priceDifference, Line 8: const percentageChange
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// Converts string with commas ("10,000") to number (10000) for mathematical calculations
+// replaceAll(",", "") removes commas, Number() converts string to number
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replaceAll

Sprint-1/3-mandatory-interpret/2-time-format.js

@@ -12,14 +12,26 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
+// 6 declarations: movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, result
 
 // b) How many function calls are there?
+// 1 function call: console.log(result)
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
-// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// % is the remainder operator - calculates remainder when dividing movieLength by 60
+// Example: 8784 % 60 = 24 (seconds that don't fit into complete minutes)
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Remainder
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// (movieLength - remainingSeconds) / 60 calculates complete minutes
+// Subtracts leftover seconds (24) from total (8784), then divides by 60 to convert to minutes
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// Represents movie length formatted as "hours:minutes:seconds"
+// Better names: formattedTime, timeString, movieDuration, formattedDuration
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Works mathematically for positive integers but has formatting issues:
+// - Single digits aren't zero-padded (shows "1:6:5" instead of "01:06:05")
+// - Negative values produce incorrect results
+// - Would need padStart() for proper time formatting

Sprint-1/3-mandatory-interpret/3-to-pounds.js

@@ -25,3 +25,26 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+// Removes trailing "p" from "399p" to get "399"
+// substring(0, 3) extracts characters from index 0 to 2
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+// Ensures string has at least 3 characters by adding leading zeros
+// "399" stays "399", but "9" would become "009" (for 9p = £0.09)
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+// Extracts all except last 2 characters for pounds
+// "399" → substring(0, 1) → "3" (£3)
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+// Extracts last 2 characters for pence and pads to 2 digits
+// "399" → substring(1) → "99", then padEnd(2, "0") → "99"
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd
+
+// 6. console.log(`£${pounds}.${pence}`);
+// Formats and displays result using template literal: "£3.99"
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals