Cape Town | 26-ITP-Sep | Quentin Gwele | Sprint 3 | coursework: sprint 3

Sprint-3/1-key-errors/0.js

@@ -1,13 +1,24 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  ==============> write your prediction here
+// I predict this will throw a SyntaxError, because the parameter 'str' is
+// being redeclared with 'let' inside the function.
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
+  let result = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return result;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+console.log(capitalise("hello"));
+
+// ==============> write your explanation here
+// The parameter 'str' already existed in the function's scope. The original
+// code tried to declare another variable with 'let str', which caused a
+// naming collision — JavaScript doesn't allow redeclaring a variable with
+// 'let' in the same scope. This threw a SyntaxError before the function
+// could even run. Renaming the new variable to 'result' fixes the collision.
+
+// ==============> write your new code here
+// (the fixed function above already satisfies this)

Sprint-3/1-key-errors/1.js

@@ -1,20 +1,33 @@
 // Predict and explain first...
-
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+//  ==============> write your prediction here
+// I predict this will throw a SyntaxError, because 'decimalNumber' is being
+// redeclared with 'const' inside the function, even though it's already the
+// function's parameter.
 
 // Try playing computer with the example to work out what is going on
 
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
 
   return percentage;
 }
 
-console.log(decimalNumber);
+console.log(convertToPercentage(0.5));
 
-// =============> write your explanation here
+// ==============> write your explanation here
+// 'decimalNumber' was already declared as the function's parameter. The
+// original code tried to declare another variable with the same name using
+// 'const decimalNumber = 0.5;', which caused a naming collision — JavaScript
+// doesn't allow redeclaring a variable in the same scope. This threw a
+// SyntaxError before the function could run.
+//
+// There was also a second issue: the original 'console.log(decimalNumber);'
+// was outside the function, so 'decimalNumber' didn't exist there (it's
+// scoped only inside 'convertToPercentage'), and the function was never
+// actually called. The fix removes the duplicate declaration and calls
+// convertToPercentage(0.5) directly, logging its return value instead.
 
 // Finally, correct the code to fix the problem
-// =============> write your new code here
+// ==============> write your new code here
+// (the fixed function above already satisfies this)

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

@@ -1,20 +1,31 @@
-
 // Predict and explain first BEFORE you run any code...
 
-// this function should square any number but instead we're going to get an error
-
-// =============> write your prediction of the error here
+// this function should square any number but instead we're getting an error
+//  ==============> write your prediction of the error here
+// I predict this will throw a SyntaxError, because '3' is used as the
+// parameter name in 'function square(3)', and a number can't be used as a
+// parameter name — parameter names must be valid identifiers (like variable
+// names).
 
-function square(3) {
-    return num * num;
+function square(num) {
+  return num * num;
 }
 
-// =============> write the error message here
-
-// =============> explain this error message here
+console.log(square(3));
 
-// Finally, correct the code to fix the problem
-
-// =============> write your new code here
+// ==============> write the error message here
+// SyntaxError: Unexpected number
 
+// ==============> explain this error message here
+// Function parameters must be valid identifiers — the same rules as variable
+// names (they must start with a letter, '$', or '_', never a digit). The
+// original code used '3' as the parameter name, which isn't a valid
+// identifier, so JavaScript couldn't even parse the function definition.
+// This error happens before any code runs. There was also a second bug: the
+// function body referred to 'num', which didn't match the (invalid)
+// parameter name at all — fixing the parameter name to 'num' resolves both
+// issues at once.
 
+// Finally, correct the code to fix the problem
+// ==============> write your new code here
+// (the fixed function above already satisfies this)

Sprint-3/2-mandatory-debug/0.js

@@ -1,14 +1,26 @@
 // Predict and explain first...
-
-// =============> write your prediction here
+//  ==============> write your prediction here
+// I predict this will run without an error, but print the wrong result at
+// the end. The 'multiply' function uses console.log internally instead of
+// returning a value, so when it's used inside the template literal, it will
+// show as 'undefined' instead of the actual multiplication result.
 
 function multiply(a, b) {
-  console.log(a * b);
+  return a * b;
 }
 
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
-// =============> write your explanation here
+// ==============> write your explanation here
+// The original 'multiply' function printed the result with console.log
+// instead of returning it. A function that doesn't explicitly return a value
+// returns 'undefined' by default. When the outer console.log tried to use
+// multiply(10, 32) inside the template literal, it inserted 'undefined'
+// instead of the actual number, because it was using the function's return
+// value, not what it printed internally. Changing console.log to return
+// inside the function fixes this, since now the function actually hands
+// back the calculated value.
 
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+// ==============> write your new code here
+// (the fixed function above already satisfies this)

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

@@ -1,13 +1,27 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  ==============> write your prediction here
+// I predict this will run without an error, but the result will show as
+// 'undefined' instead of the actual sum. The 'return' statement is on its
+// own line, separate from 'a + b;' on the next line — JavaScript will treat
+// these as two separate statements, so the function returns immediately
+// with nothing, and 'a + b' never actually gets returned.
 
 function sum(a, b) {
-  return;
-  a + b;
+  return a + b;
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
+// ==============> write your explanation here
+// JavaScript has a feature called Automatic Semicolon Insertion (ASI). When
+// 'return' appears on its own line with nothing after it, JavaScript
+// automatically treats it as 'return;' — ending the function right there and
+// returning 'undefined'. The following line, 'a + b;', becomes dead code
+// that never runs, because the function has already exited. This is why the
+// original code always produced 'undefined' instead of the sum. The fix is
+// to put the expression on the same line as 'return', so JavaScript knows
+// it's part of the return statement: 'return a + b;'.
+
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+// ==============> write your new code here
+// (the fixed function above already satisfies this)

Sprint-3/2-mandatory-debug/2.js

@@ -1,7 +1,11 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+//  ==============> write your prediction here
+// I predict every call to getLastDigit will return the same result: "3",
+// no matter what number is passed in. This is because the function doesn't
+// take any parameters — it always uses the outer 'num' variable (103)
+// instead of the value passed into the function call.
 
 const num = 103;
 
@@ -14,11 +18,13 @@ console.log(`The last digit of 105 is ${getLastDigit(105)}`);
 console.log(`The last digit of 806 is ${getLastDigit(806)}`);
 
 // Now run the code and compare the output to your prediction
-// =============> write the output here
-// Explain why the output is the way it is
-// =============> write your explanation here
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+//  ==============> write the output here
+// The last digit of 42 is 3
+// The last digit of 105 is 3
+// The last digit of 806 is 3
 
-// This program should tell the user the last digit of each number.
-// Explain why getLastDigit is not working properly - correct the problem
+// Explain why the output is the way it is
+//  ==============> write your explanation here
+// The function getLastDigit() is defined with no parameters, so the values
+// 42, 105, and 806 passed into each call are simply ignored — they go
+// nowhere. Instead, the

Sprint-3/3-mandatory-implement/1-bmi.js

@@ -15,5 +15,10 @@
 // It should return a string of their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
-  // return the BMI of someone based off their weight and height
+  const bmi = weight / (height * height);
+  return bmi.toFixed(1);
 }
+
+console.log(calculateBMI(70, 1.73));
+console.log(calculateBMI(60, 1.6));
+console.log(calculateBMI(90, 1.85));

Sprint-3/3-mandatory-implement/2-cases.js

@@ -14,3 +14,10 @@
 // You will need to come up with an appropriate name for the function
 // Use the MDN string documentation to help you find a solution
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+
+function convertToUpperSnakeCase(str) {
+  return str.toUpperCase().split(' ').join('_');
+}
+
+console.log(convertToUpperSnakeCase("hello there"));
+console.log(convertToUpperSnakeCase("lord of the rings"));

Sprint-3/3-mandatory-implement/3-to-pounds.js

@@ -4,3 +4,11 @@
 // You will need to declare a function called toPounds with an appropriately named parameter.
 
 // You should call this function a number of times to check it works for different inputs
+
+function toPounds(kg) {
+  return kg * 2.20462;
+}
+
+console.log(toPounds(70));
+console.log(toPounds(60));
+console.log(toPounds(90));

Sprint-3/4-mandatory-interpret/time-format.js

@@ -11,28 +11,41 @@ function formatTimeDisplay(seconds) {
   const totalMinutes = (seconds - remainingSeconds) / 60;
   const remainingMinutes = totalMinutes % 60;
   const totalHours = (totalMinutes - remainingMinutes) / 60;
-
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
-// You will need to play computer with this example - use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
+// You will need to play computer with this example – use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
 // to help you answer these questions
 
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// ==============> write your answer here
+// pad will be called 3 times — once for totalHours, once for remainingMinutes,
+// and once for remainingSeconds, since all three appear inside the template
+// literal on the return line.
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
 
 // b) What is the value assigned to num when pad is called for the first time?
-// =============> write your answer here
-
-// c) What is the return value of pad when it is called for the first time?
-// =============> write your answer here
-
-// d) What is the value assigned to num when pad is called for the last time in this program?  Explain your answer
-// =============> write your answer here
-
-// e) What is the return value of pad when it is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// ==============> write your answer here
+// num = 0 (this is totalHours, since (61-1)/60 = 1 minute total, and
+// (1-1)/60 = 0 hours, and pad(totalHours) is the first call in the template
+// literal)
+
+// c) What is the return value of pad it is called for the first time?
+// ==============> write your answer here
+// "00" — pad(0) converts 0 to the string "0", which has length 1, so a
+// leading "0" is added, making it "00"
+
+// d) What is the value assigned to num when pad is called for the last time in this program? Explain your answer
+// ==============> write your answer here
+// num = 1 (this is remainingSeconds — 61 % 60 = 1 — and pad(remainingSeconds)
+// is the last of the three pad() calls in the template literal)
+
+// e) What is the return value of pad when it is called for the last time in this program? Explain your answer
+// ==============> write your answer here
+// "01" — pad(1) converts 1 to the string "1", which has length 1, so a
+// leading "0" is added, making it "01"
+
+console.log(formatTimeDisplay(61)); // "00:01:01"

Sprint-3/5-stretch-extend/format-time.js

@@ -4,12 +4,20 @@
 
 function formatAs12HourClock(time) {
   const hours = Number(time.slice(0, 2));
-  if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+  const minutes = time.slice(3);
+
+  if (hours === 0) {
+    return `12:${minutes} am`;
+  } else if (hours === 12) {
+    return `12:${minutes} pm`;
+  } else if (hours > 12) {
+    return `${hours - 12}:${minutes} pm`;
+  } else {
+    return `${hours}:${minutes} am`;
   }
-  return `${time} am`;
 }
 
+// Original tests
 const currentOutput = formatAs12HourClock("08:00");
 const targetOutput = "08:00 am";
 console.assert(
@@ -23,3 +31,43 @@ console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`
 );
+
+// Edge case: midnight
+const currentOutput3 = formatAs12HourClock("00:00");
+const targetOutput3 = "12:00 am";
+console.assert(
+  currentOutput3 === targetOutput3,
+  `current output: ${currentOutput3}, target output: ${targetOutput3}`
+);
+
+// Edge case: noon
+const currentOutput4 = formatAs12HourClock("12:00");
+const targetOutput4 = "12:00 pm";
+console.assert(
+  currentOutput4 === targetOutput4,
+  `current output: ${currentOutput4}, target output: ${targetOutput4}`
+);
+
+// Edge case: PM time with non-zero minutes (checks minutes aren't lost)
+const currentOutput5 = formatAs12HourClock("13:45");
+const targetOutput5 = "1:45 pm";
+console.assert(
+  currentOutput5 === targetOutput5,
+  `current output: ${currentOutput5}, target output: ${targetOutput5}`
+);
+
+// Edge case: one minute before midnight
+const currentOutput6 = formatAs12HourClock("23:59");
+const targetOutput6 = "11:59 pm";
+console.assert(
+  currentOutput6 === targetOutput6,
+  `current output: ${currentOutput6}, target output: ${targetOutput6}`
+);
+
+// Edge case: noon with non-zero minutes
+const currentOutput7 = formatAs12HourClock("12:15");
+const targetOutput7 = "12:15 pm";
+console.assert(
+  currentOutput7 === targetOutput7,
+  `current output: ${currentOutput7}, target output: ${targetOutput7}`
+);