ITP-JAN-25 | Sulaiman Kamara | London Brixton Office | Module-Structuring-and-Testing-Data | Sprint 2, Issue 02

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

@@ -4,3 +4,5 @@ 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
+
+// Explanation: In Line 3, the '=' is reassigning the 'count' variable to the current value of 'count' plus 1 i.e. incrementing 'count' by 1.

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

@@ -5,7 +5,16 @@ 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
 
+// MY SOLUTION START //
+
+// Get first character of each name, store it in a string, and remove spaces with trim().
+let initials = `${firstName.charAt(0)}${middleName.charAt(0)}${lastName.charAt(
+  0
+)}`.trim();
+
+// View output to check if 'initals' variable matches the expected output 'CKJ'.
+console.log(initials);
+
+// MY SOLUTION END //

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

@@ -11,13 +11,14 @@
 
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
+const indexOfDot = filePath.indexOf("."); // Get index of '.'
 const base = filePath.slice(lastSlashIndex + 1);
-console.log(`The base part of ${filePath} is ${base}`);
+const dir = filePath.slice(0, lastSlashIndex); // 1. Create a variable to store the dir part of the filePath variable
+const ext = filePath.slice(indexOfDot); // 2. Create a variable to store the ext part of the variable
 
-// Create a variable to store the dir part of the filePath variable
-// Create a variable to store the ext part of the variable
+// Output
+console.log(`1. Dir - "${dir}"`);
+console.log(`2. Ext - "${ext}"`);
+console.log(`3. The base part of "${filePath}" is "${base}"`);
 
-const dir = ;
-const ext = ;
-
-// https://www.google.com/search?q=slice+mdn
+// Resource - https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,13 @@ const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 // 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
+
+// DOCUMENTATION
+// 'num' - generates a random number within range between 'minimum' and 'maximum'.
+// Math.floor() - rounds any number down to the nearest whole number.
+// Math.random() - generates a random number between 0 and 0.9 recurring (never 1).
+// '* (maximum - minimum + 1)' - Calculates range. '+ 1' means generated number can actually be <= range instead of just < range.
+// '+ minimum' - totals the minimum and maximum to get the total range.
+
+// Output
+console.log(num);

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

@@ -1,2 +1,2 @@
-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?

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

@@ -2,3 +2,5 @@
 
 const age = 33;
 age = age + 1;
+
+// You cannot reassign a constant variable. To create a variable that needs to be reassigned, the 'let' keyword should be used instead of 'const'.

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

@@ -3,3 +3,5 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+// 'let' and 'const' variables can only be used after their declaration

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

@@ -1,4 +1,4 @@
-const cardNumber = 4533787178994213;
+const cardNumber = [4, 5, 3, 3, 7, 8, 7, 1, 7, 8, 9, 9, 4, 2, 1, 3];
 const last4Digits = cardNumber.slice(-4);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
@@ -7,3 +7,10 @@ const last4Digits = cardNumber.slice(-4);
 // 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
+
+// Prediction: slice takes an index or index range, and I don't think you can have negative indexes, so that will be the error.
+// Outcome: says '.slice' is not a function
+// Fix: slice is an array method not a string method. convert card number into an array.
+
+// Output
+console.log(last4Digits);

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

@@ -1,2 +1,3 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+// Variable names can't start with a number.
+const hour24ClockTime = "20:53";
+const hour12ClockTime = "08:53";

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

@@ -2,7 +2,7 @@ let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", "")); // missing a comma
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -13,10 +13,20 @@ console.log(`The percentage change is ${percentageChange}`);
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
 
+// 4 function calls, in lines 4, 5, 8, and 10.
+
 // 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?
 
+// line 5 two values are passed into the replaceAll method, but aren't comma separated. Fixed error, by separating values with a comma.
+
 // c) Identify all the lines that are variable reassignment statements
 
+// In lines 4 and 5, 'priceDifference' and 'priceAfterOneYear' are reassigned.
+
 // d) Identify all the lines that are variable declarations
 
+// 1, 2, 7, 8 are all variable declarations, and 4 and 5 are variable redeclarations.
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+// Type conversion: converts values from string to number, in order to be used in calculations later on in the program.

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

@@ -13,13 +13,25 @@ console.log(result);
 
 // a) How many variable declarations are there in this program?
 
+// Answer: 6
+
 // b) How many function calls are there?
 
+// Answer: 1 - 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
 
+// Answer: It sees how many whole minutes go into the movieLength, and tells you what was left over.
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+// Answer: It gets the total length of the movie in seconds, divides it by 60 to get the total length of the movie in minutes.
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+// Answer: It represents the current time in the movie, so maybe 'timestamp' could be a better name.
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// Answer: Negative values don't make sense. Long decimals aren't rounded. But positive integers work.

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

@@ -10,7 +10,7 @@ const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
-
+// 0399
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
@@ -25,3 +25,8 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 2. penceStringWithoutTrailingP: separates the number from the 'p', so it's now "399"
+// 3. paddedPenceNumberString: adds a 0 to the start, so it's "0399"
+// 4. pounds: extracts the first 2 characters to get the pounds, so it's "03"
+// 5. pence: gets all the characters after 2nd character, so it's "99". The 'padEnd(2)' makes sure there is always two digits for the pence part
+// 6. 'console.log(`£${pounds}.${pence}`): logs the amount in pounds and pence, with a dot separating the two.

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

@@ -1,13 +1,15 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  Capitalise 1st letter of a string.
 
 // call the function capitalise with a string input
-// interpret the error message and figure out why an error is occurring
+capitalise("String input.");
 
-function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
-}
+// interpret the error message and figure out why an error is occurring
 
 // =============> write your explanation here
+// The error occurs because you cannot declare a variable with a name that exists in the same scope.
+
 // =============> write your new code here
+function capitalise(str) {
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
+}

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

@@ -2,19 +2,20 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// Undefined, decimalNumber is not in the right scope for the console.log statement to access it.
 
 // Try playing computer with the example to work out what is going on
 
+// =============> write your explanation here
+// Declaring variable with the same name in the same scope causes error.
+
+// Finally, correct the code to fix the problem
+// =============> write your new code here
+const decimalNumber = 0.5;
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
 
   return percentage;
 }
 
-console.log(decimalNumber);
-
-// =============> write your explanation here
-
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+console.log(convertToPercentage(decimalNumber));

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

@@ -1,20 +1,22 @@
-
 // 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
-
-function square(3) {
-    return num * num;
-}
+// Answer: Cant set a value as a parameter (error)
 
 // =============> write the error message here
+// Answer: SyntaxError: Unexpected number. Identifier expected.
 
 // =============> explain this error message here
+// Answer: The error message means a number is being used in a place where it is syntactically invalid.
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
+// Answer:
+function square(num) {
+  return num * num;
+}
 
-
+console.log(square(3));

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

@@ -1,14 +1,15 @@
 // Predict and explain first...
 
 // =============> write your prediction here
-
-function multiply(a, b) {
-  console.log(a * b);
-}
-
-console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+// Answer: logs the product of 2 numbers to the console.
 
 // =============> write your explanation here
+// Answer: multiples 2 numbers, and logs them to the console. However the function doesn't include a return statement, so the output of the function will default to 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

@@ -1,13 +1,15 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// Answer: function returns nothing (undefined), because it is on a different line from the return statement and isn't wrapped in parentheses ().
 
+// =============> write your explanation here
+// Answer: function calls of sum() return undefined as the statement is on a separate line from the return statement without braces ().
+
+// Finally, correct the code to fix the problem
+//  =============> write your new code here
+// Answer:
 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
-// Finally, correct the code to fix the problem
-//  =============> write your new code here

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

@@ -2,23 +2,27 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// Answer: Error because parameters aren't defined, but arguments are passed in.
 
+// Now run the code and compare the output to your prediction
+// =============> write the output here
+// Answer: It just gets the last digit of the variable 'num'.
+
+// Explain why the output is the way it is
+// =============> write your explanation here
+// Answer: Parameters aren't defined, so arguments being passed in arent used, so it just uses the 'num' variable referenced within the function as opposed to the arguments passed in.
+
+// This program should tell the user the last digit of each number.
+// Explain why getLastDigit is not working properly - correct the problem
+// Finally, correct the code to fix the problem
+// =============> write your new code here
+// Answer:
 const num = 103;
 
-function getLastDigit() {
+function getLastDigit(num) {
   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)}`);
-
-// 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
-
-// This program should tell the user the last digit of each number.
-// Explain why getLastDigit is not working properly - correct the problem

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

@@ -15,5 +15,8 @@
 // It should return their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
+  // return the BMI of someone based off their weight and height
+  return Number((weight / (height * 2)).toFixed(1));
+}
+
+console.log(calculateBMI(85, 1.81));

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

@@ -14,3 +14,9 @@
 // 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
+// Answer:
+function upperSnakeCase(string) {
+  return string.toUpperCase().split(" ").join("_");
+}
+
+console.log(upperSnakeCase("I am a string"));

Sprint-2/3-mandatory-implement/3-to-pounds.js

@@ -4,3 +4,22 @@
 // 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 penceStringWithoutTrailingP = penceString.substring(
+    0,
+    penceString.length - 1
+  );
+
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+  const pounds = paddedPenceNumberString.substring(
+    0,
+    paddedPenceNumberString.length - 2
+  );
+
+  const pence = paddedPenceNumberString
+    .substring(paddedPenceNumberString.length - 2)
+    .padEnd(2, "0");
+
+  return `£${pounds}.${pence}`;
+}
+console.log(toPounds("98765532626p"));