London | 26-ITP-May | Chinwe Chukwuma | Sprint 2 | Module-Structuring-and-Testing-Data

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

@@ -1,13 +1,21 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// I predict it will throw a SyntaxError because the variable 'str' has already being declared in the function parameter. And JavaScript will not allow it.
 
 // 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;
 }
 
 // =============> write your explanation here
+/*  it throws a SyntaxError: Identifier 'str' has already been declared because the function parameter 'str' is already a variable in the function scope. 
+The line `let str = ...` tries to create a new variable str in the same scope, which is not allowed in JavaScript. To fix this, we can either rename the parameter or the variable inside the function. */
+
 // =============> write your new code here
+function capitalise(str) {
+  return str[0].toUpperCase() + str.slice(1);
+}

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

@@ -2,6 +2,9 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+/* I predict that it will throw a SyntaxError because decimalNumber is declared twice inside the same function, 
+and JvaScript does not allow redeclaring a variable with const in the same scope. 
+It will also throw a ReferenceError because decimalNumber is logged outside the function, where it is not defined. */
 
 // Try playing computer with the example to work out what is going on
 
@@ -15,6 +18,16 @@ function convertToPercentage(decimalNumber) {
 console.log(decimalNumber);
 
 // =============> write your explanation here
+/* The function receives decimalNumber as a parameter, so that variable already exists in the function scope. Declaring const decimalNumber = 0.5; 
+inside the function attempts to create a second variable with the same name, which causes a SyntaxError. Additionally, the console.log(decimalNumber) is outside the function, so JavaScript cannot
+find a variable called decimalNumber in that scope, which causes a ReferenceError. */ 
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+  return percentage;
+}
+
+console.log(convertToPercentage(0.5));
+

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

@@ -4,17 +4,27 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+/* I predict that it will throw a SyntaxError because the function parameter is written as 3, which is not a valid variable
+name. Function parameters should be names (like num, x,) or any other valid identifier, not a number. */ 
 
 function square(3) {
     return num * num;
 }
 
+
 // =============> write the error message here
+// SyntaxError: Unexpected number
 
 // =============> explain this error message here
+/* The function is declared with 3 as its parameter, but JavaScript only allows variable names(identifiers)
+in that position. Using a number causes a SyntaxError before the code is run. 
+Also, the function tries to t=return num * num, but num is not defined, which would cause a ReferenceError if the first error did not occur.*/
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
+function square(num) {
+    return num * num;
+}
 
-
+console.log(square(25));

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

@@ -1,6 +1,8 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+/* The code will return "The result of multiplying 10 and 32 is undefined" because the function logs the result instead of returning it. 
+Multiply(10, 32) returns udefined, and that's what gets inserted into the template string. */
 
 function multiply(a, b) {
   console.log(a * b);
@@ -9,6 +11,15 @@ function multiply(a, b) {
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+/* Inside the function, console.log(a * b) prints the answer to the console, but the function does not return any value, so it returns undefined. 
+when we call multiply(10, 32) ,the function prints 320 to the console, but the return value of the function is undefined.
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`); inserts the returned value, not the logged value. Since the function returns undefined,
+the final output becomes "The result of multiplying 10 and 32 is undefined". */
 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
 //  =============> write your prediction here
+/* Because the function has a return statement with nothing after it, the code will return: The sum of 10 and 32 is udefined.
+The line a + b will never run because it comes after the return. */
 
 function sum(a, b) {
   return;
@@ -9,5 +11,14 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+/* When JavaScript sees a return statement, it immediately stops the function. So the function exits before it ever reaches a + b. 
+Because nothing is returned, JavaScript returns undefined. The template string uses the returned value. The line: console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+inserts whatever the function returns. since the function returns undefined, the final output becomes: The sum of 10 and 32 is undefined. Even though a + b is written in the function, it returns undefined. */ 
+
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);

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

@@ -2,6 +2,13 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+/* All the three lines will output the last digits of 103, which is "3". So the output will be:
+The last digit of 42 is 3
+The last digit of 105 is 3
+The last digit of 806 is 3
+
+This is because the function getLastDigit() does not use the number passed into it.
+Instead, it is always uses the global variable 'num', which is 103. therefore, every call returns the last digit of 103. */
 
 const num = 103;
 
@@ -15,10 +22,45 @@ 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
+
+/* The output will be:
+The last digit of 42 is 3
+The last digit of 105 is 3
+The last digit of 806 is 3 
+*/
+
+
 // Explain why the output is the way it is
 // =============> write your explanation here
+
+/* The function getLastDigit() is supposed to return the last digit of the number passed to it by the user. However, the function does not accept any parameters.
+Even though the function is called with values like getLastDigit(42), getLastDigit(105), and getLastDigit(806), the argument is ignored because the function definition does not include a parameter. 
+Instead, the function always uses the global variable 'num', which is 103.
+The last digit of 103 is "3", so every call returns "3" regardless of the number passed in. */
+
+
 // 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
+
+/* getLastDigit is not working properly because it does not accept any parameters in its definition. 
+As a result, it always uses the global variable 'num', which is set to 103, instead of using the number passed to it when called.
+The correct code now includes a parameter 'number' in the function definition of getLastDigit(). 
+This allows the function to accept the number passed to it when called.
+
+Correct Output:
+The last digit of 42 is 2
+The last digit of 105 is 5
+The last digit of 806 is 6
+ */

Sprint-2/3-mandatory-implement/1-bmi.js

@@ -16,4 +16,8 @@
 
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+    const bmi = (weight / height **2);
+    return bmi.toFixed(1);
+}
+
+console.log(calculateBMI(90, 1.80));

Sprint-2/3-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(text) {
+    return text.toUpperCase().replaceAll(" ", "_");
+}
+
+console.log(toUpperSnakeCase("hello there"));
+console.log(toUpperSnakeCase("lord of the rings"));
+console.log(toUpperSnakeCase("javascript is challenging and fun"));

Sprint-2/4-mandatory-interpret/time-format.js

@@ -22,17 +22,22 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// 3 times
 
 // 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
+// 0
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
+// 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
+// The value assigned is "1"  because remainingSeconds was calculated as 61 % 60, which equals 1, and that is passed into pad last.
 
 // 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
+// The return value is "01"  because  pad always ensures te output is atleast 2 characters long, so 1 becomes "01".

Sprint-2/5-stretch-extend/format-time.js

@@ -23,3 +23,64 @@ console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`
 );
+
+// Midnight
+console.assert(
+  formatAs12HourClock("00:00") === "12:00 am",
+  "00:00 should be 12:00 am"
+);
+
+// Noon
+console.assert(
+  formatAs12HourClock("12:00") === "12:00 pm",
+  "12:00 should be 12:00 pm"
+);
+
+// Minutes included
+console.assert(
+  formatAs12HourClock("14:45") === "2:45 pm",
+  "14:45 should be 2:45 pm"
+);
+
+// Single-digit hour AM
+console.assert(
+  formatAs12HourClock("09:30") === "9:30 am",
+  "09:30 should be 9:30 am"
+);
+
+// Single-digit hour PM
+console.assert(
+  formatAs12HourClock("13:05") === "1:05 pm",
+  "13:05 should be 1:05 pm"
+);
+
+// Edge: 12:59 PM
+console.assert(
+  formatAs12HourClock("12:59") === "12:59 pm",
+  "12:59 should be 12:59 pm"
+);
+
+// Edge: 00:59 AM
+console.assert(
+  formatAs12HourClock("00:59") === "12:59 am",
+  "00:59 should be 12:59 am"
+);
+
+function formatAs12HourClock(time) {
+  const [hourStr, minuteStr] = time.split(":");
+  let hours = Number(hourStr);
+  const minutes = minuteStr;
+
+  let period = "am";
+
+  if (hours === 0) {
+    hours = 12; // midnight
+  } else if (hours === 12) {
+    period = "pm"; // noon
+  } else if (hours > 12) {
+    hours -= 12;
+    period = "pm";
+  }
+
+  return `${hours}:${minutes} ${period}`;
+}