North West | 26-ITP-Sep | Brian Yorachi | Sprint 3 | Course work/sprint 3

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

@@ -1,13 +1,18 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// Prediction: Node will report a SyntaxError because str is declared twice in
+// the same function scope: once as a parameter and again with let.
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
+// Faulty line from the original: let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+
+// Error: SyntaxError: Identifier 'str' has already been declared
+// Explanation: A function parameter is already a binding in the function body.
+// Declaring another let binding with the same name is not allowed.
+// Corrected code:
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+console.log(capitalise("hello"));

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

@@ -1,20 +1,23 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// Prediction: Node will report a SyntaxError because decimalNumber is declared
+// as a const inside the function even though it is already a 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);
+// Faulty original lines:
+// const decimalNumber = 0.5; // duplicates the parameter inside the function
+// console.log(decimalNumber); // refers to the parameter outside its scope
 
-// =============> write your explanation here
+// Error: SyntaxError: Identifier 'decimalNumber' has already been declared
+// Explanation: The parameter already declares decimalNumber in the function
+// scope. The inner const declaration duplicates that binding. Also, the final
+// console.log refers to a name that would not be available outside the function.
 
 // Finally, correct the code to fix the problem
-// =============> write your new code here
+function convertToPercentage(decimalNumber) {
+  return `${decimalNumber * 100}%`;
+}
+
+console.log(convertToPercentage(0.5));

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

@@ -3,18 +3,22 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// Prediction: Node will report a SyntaxError because a number cannot be used
+// as a function parameter name.
 
-function square(3) {
-    return num * num;
-}
+// Faulty original: function square(3) { return num * num; }
 
-// =============> write the error message here
+// Error: SyntaxError: Unexpected number
 
-// =============> explain this error message here
+// Explanation: Function parameters must be identifiers such as num, not literal
+// values such as 3. The body also refers to num, which was never declared.
 
 // Finally, correct the code to fix the problem
 
-// =============> write your new code here
+function square(num) {
+    return num * num;
+}
+
+console.log(square(3));
 
 

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

@@ -1,14 +1,23 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// Prediction: The multiplication itself prints 320, but the template string
+// then shows undefined because multiply does not return the result.
 
-function multiply(a, b) {
+function multiplyBeforeFix(a, b) {
   console.log(a * b);
 }
 
+console.log(`The result of multiplying 10 and 32 is ${multiplyBeforeFix(10, 32)}`);
+
+function multiply(a, b) {
+  return a * b;
+}
+
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
-// =============> write your explanation here
+// Observed before the fix: 320, then "undefined" in the template string.
+// Explanation: console.log displays the product but returns undefined. The
+// function call inside the template string therefore evaluates to undefined.
 
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+// The corrected function above returns the product for the template string.

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

@@ -1,13 +1,22 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// Prediction: The output will say undefined because return exits the function
+// before the addition expression can run.
 
-function sum(a, b) {
+function sumBeforeFix(a, b) {
   return;
   a + b;
 }
 
+console.log(`The sum of 10 and 32 is ${sumBeforeFix(10, 32)}`);
+
+function sum(a, b) {
+  return a + b;
+}
+
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
+// Observed before the fix: undefined.
+// Explanation: A newline immediately after return ends the return statement.
+// The function returns undefined and the following expression is unreachable.
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+// The corrected function above returns the sum.

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

@@ -1,24 +1,32 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+// Prediction: Each line reports 103's last digit (3), because getLastDigit
+// ignores its arguments and always reads the global num variable.
 
 const num = 103;
 
-function getLastDigit() {
+function getLastDigitBeforeFix() {
   return num.toString().slice(-1);
 }
 
-console.log(`The last digit of 42 is ${getLastDigit(42)}`);
-console.log(`The last digit of 105 is ${getLastDigit(105)}`);
-console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+console.log(`The last digit of 42 is ${getLastDigitBeforeFix(42)}`);
+console.log(`The last digit of 105 is ${getLastDigitBeforeFix(105)}`);
+console.log(`The last digit of 806 is ${getLastDigitBeforeFix(806)}`);
 
 // Now run the code and compare the output to your prediction
-// =============> write the output here
+// Output: Each line reports 3.
 // Explain why the output is the way it is
-// =============> write your explanation here
+// Explanation: getLastDigit has no parameter and reads the unchanged global
+// num (103), so passing 42, 105, or 806 has no effect.
 // Finally, correct the code to fix the problem
-// =============> write your new code here
+function getLastDigit(number) {
+  return number.toString().slice(-1);
+}
+
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
 
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem

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

@@ -15,5 +15,8 @@
 // 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
+  return (weight / height ** 2).toFixed(1);
 }
+
+console.log(calculateBMI(70, 1.73));
+console.log(calculateBMI(60, 1.65));

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

@@ -14,3 +14,11 @@
 // 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 toUpperSnakeCase(input) {
+  return input.trim().replace(/\s+/g, "_").toUpperCase();
+}
+
+console.log(toUpperSnakeCase("hello there"));
+console.log(toUpperSnakeCase("lord of the rings"));
+console.log(toUpperSnakeCase("  multiple   spaces  "));

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

@@ -4,3 +4,18 @@
 // 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(penceString) {
+	const penceDigits = penceString.endsWith("p")
+		? penceString.slice(0, -1)
+		: penceString;
+	const paddedPence = penceDigits.padStart(3, "0");
+	const pounds = paddedPence.slice(0, -2);
+	const pence = paddedPence.slice(-2);
+
+	return `£${pounds}.${pence}`;
+}
+
+console.log(toPounds("399p"));
+console.log(toPounds("9p"));
+console.log(toPounds("1200p"));

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

@@ -15,24 +15,26 @@ function formatTimeDisplay(seconds) {
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
+console.log(formatTimeDisplay(61));
+
 // 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
+// Answer: Three times, once for hours, once for minutes, and once for seconds.
 
 // 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
+// Answer: 0, because 61 seconds contains 0 whole hours.
 
 // c) What is the return value of pad when it is called for the first time?
-// =============> write your answer here
+// Answer: "00". pad converts 0 to a string and prepends a zero.
 
 // 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
+// Answer: 1, because the remaining seconds after 61 is divided into minutes is 1.
 
 // 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
+// Answer: "01", because pad converts 1 to a string and prepends a zero.

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

@@ -2,24 +2,31 @@
 // Make sure to do the prep before you do the coursework
 // Your task is to write tests for as many different groups of input data or edge cases as you can, and fix any bugs you find.
 
+const assert = require("node:assert/strict");
+
 function formatAs12HourClock(time) {
-  const hours = Number(time.slice(0, 2));
-  if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+  if (typeof time !== "string" || !/^(?:[01]\d|2[0-3]):[0-5]\d$/.test(time)) {
+    throw new RangeError("time must be a valid 24-hour time in HH:MM format");
   }
-  return `${time} am`;
+
+  const hours = Number(time.slice(0, 2));
+  const displayHours = String(hours % 12 || 12).padStart(2, "0");
+  const minutes = time.slice(3);
+  const period = hours < 12 ? "am" : "pm";
+
+  return `${displayHours}:${minutes} ${period}`;
 }
 
-const currentOutput = formatAs12HourClock("08:00");
-const targetOutput = "08:00 am";
-console.assert(
-  currentOutput === targetOutput,
-  `current output: ${currentOutput}, target output: ${targetOutput}`
-);
+assert.equal(formatAs12HourClock("00:00"), "12:00 am");
+assert.equal(formatAs12HourClock("00:05"), "12:05 am");
+assert.equal(formatAs12HourClock("08:00"), "08:00 am");
+assert.equal(formatAs12HourClock("11:59"), "11:59 am");
+assert.equal(formatAs12HourClock("12:00"), "12:00 pm");
+assert.equal(formatAs12HourClock("12:45"), "12:45 pm");
+assert.equal(formatAs12HourClock("13:07"), "01:07 pm");
+assert.equal(formatAs12HourClock("23:59"), "11:59 pm");
+assert.throws(() => formatAs12HourClock("24:00"), RangeError);
+assert.throws(() => formatAs12HourClock("12:60"), RangeError);
+assert.throws(() => formatAs12HourClock("8:00"), RangeError);
 
-const currentOutput2 = formatAs12HourClock("23:00");
-const targetOutput2 = "11:00 pm";
-console.assert(
-  currentOutput2 === targetOutput2,
-  `current output: ${currentOutput2}, target output: ${targetOutput2}`
-);
+console.log("All formatAs12HourClock tests passed.");