London | 26-ITP-January | Karla Grajales | Sprint 1 | coursework/sprint-1

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

@@ -2,5 +2,9 @@ let count = 0;
 
 count = count + 1;
 
+console.log(count);
+
 // 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 is reassigning the value of count by adding 1 to its current value.

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

@@ -4,8 +4,13 @@ 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.
+// https://www.google.com/search?q=get+first+character+of+string+mdn
+
+const initials = firstName.charAt(0) + middleName.charAt(0) + lastName.charAt(0);
+console.log(`initials = ${initials}`);
+
+
+
 
-let initials = ``;
 
-// https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

@@ -12,12 +12,23 @@
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
 const base = filePath.slice(lastSlashIndex + 1);
-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 lastDot = filePath.lastIndexOf(".");
+console.log(`The indexDot is ${lastDot}`);
+
+const ext = filePath.slice(lastDot);
+
+const fileName = filePath.slice(lastSlashIndex + 1, lastDot);
+const dir = filePath.slice(1, lastSlashIndex + 1);
+
+
+
+console.log(`The dir is 👉 ${dir}`);
+console.log(`The nameFile is 👉 ${fileName}`);
+console.log(`The extension is 👉 ${ext}`);
+
+
 
-// https://www.google.com/search?q=slice+mdn

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

@@ -1,9 +1,31 @@
+// 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
+
 const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+//this line will generate a random number between minimum and maximum (inclusive)
+// and math.floor will remove decimal part 
+
+Math.floor() //removes decimal part and returns whole number
+Math.random() //needs to values between minimum and maximum to generate a random number
+
+console.log(maximum - minimum + 1 ) + minimum; // this is same as 100 - 1 + 1 = 100 
+console.log(`The random number is ${num}`);
+
+
+// breaking down the expressions
+// We subtract the minimum from the maximum to find the absolute range (the distance) 
+// between the two numbers. This tells Math.random() how many possible values it needs 
+// to generate. We add it back at the end to shift the starting point from 0 to our desired minimum.
+
+
+// 1. Range = (100 - 1 + 1) -> We have 100 possible integers.
+// 2. Scaling = Math.random() * 100 -> Gives a decimal between 0 and 99.99.
+// 3. Integer = Math.floor(0 to 99.99) -> Gives a whole number between 0 and 99.
+// 4. Offset = (0 to 99) + 1 -> Shifts the result to be between 1 and 100.
+
 
-// 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

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

@@ -1,2 +1,7 @@
-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
+//to write comments in JavaScript, we use two forward slashes like this so, for this exercise,
+// we can comment out the two lines above to prevent them from being executed.

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

@@ -1,4 +1,7 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
-age = age + 1;
+let age = 33;
+age += 1;
+console.log(age);
+
+// We need to use 'let' to reassign a variable; 'const' does not allow reassignment.

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

@@ -1,5 +1,9 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
 
-console.log(`I was born in ${cityOfBirth}`);
+
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+
+// explanation: the error was that the variable cityOfBirth was not defined before it was used in the console.log statement. 
+

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

@@ -1,9 +1,20 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const numberString = cardNumber.toString();
+const last4Digits = numberString.slice(-4);
+const num = Number(last4Digits);
+
+console.log(num);
 
 // 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
+
+
+
+// explanation: to see the numbers correctly we need to convert the cardNumber to a string
+//  first before slicing the last 4 digits. The original code was trying to use slice 
+//  a number, which is not valid. By converting it to a string first, 
+//  we can then slice the last 4 characters correctly. Then we convert it back to a number.

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

@@ -1,2 +1,11 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+
+// explanation: the first lines will throw an error because js detect a number instead of a variable name, 
+// so we move the number to the end and now it works fine.
+// const 24hourClockTime = "08:53;
+// const 12HourClockTime = "20:53";
+
+
+const clock12h = "20:53";
+const clock24h = "08:53";
+console.log(clock12h);
+console.log(clock24h);

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(",", ""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -13,10 +13,48 @@ 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
 
+    // There are 5 function calls in this file:
+    // Line 4: Number() and replaceAll(",", "")
+    // Line 5: Number() and replaceAll(",", "")  
+    // 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?
+
+    // The error was line 5, carPrice.replaceAll("," ""); missing the comma between the arguments
 
 // c) Identify all the lines that are variable reassignment statements
 
+    //line 4, line 5, 
+
 // d) Identify all the lines that are variable declarations
 
+    // line 1, line 2, line 7 and line 8
+
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+    // First, replaceAll(",", "") removes the commas from the string because JavaScript 
+    // cannot perform math on strings containing symbols. It turns "10,000" into "10000".
+
+    // Then, the Number() function converts that clean string into an actual number.
+    // The purpose is to prepare the data for calculation; without this, JavaScript 
+    // would return NaN (Not a Number) when trying to subtract the prices.
+
+
+// ---------- console.log each step to see the results ----------
+
+    // let carPrice = "10,000";
+    // let priceAfterOneYear = "8,543";
+
+    // carPrice = Number(carPrice.replaceAll(",", ""));
+    // console.log(carPrice); // the commas are removed and the string is converted to a number
+
+    // priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+    // console.log(priceAfterOneYear); // the commas are removed and the string is converted to a number
+
+    // const priceDifference = carPrice - priceAfterOneYear;
+    // console.log(`The price difference is ${priceDifference}`);
+
+    // const percentageChange = (priceDifference / carPrice) * 100;
+    // console.log(`The percentage change is ${percentageChange}`);

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

@@ -1,7 +1,8 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 5; // length of movie in seconds
 
-const remainingSeconds = movieLength % 60;
+const remainingSeconds = movieLength % 60;   console.log(remainingSeconds);//24
 const totalMinutes = (movieLength - remainingSeconds) / 60;
+console.log(totalMinutes);//146 
 
 const remainingMinutes = totalMinutes % 60;
 const totalHours = (totalMinutes - remainingMinutes) / 60;
@@ -13,13 +14,36 @@ console.log(result);
 
 // a) How many variable declarations are there in this program?
 
+    // There are six variable declarations in this program: 
+    // movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, and result.
+
 // b) How many function calls are there?
 
+    //There is one function call in this program: console.log(result);
+    //In JavaScript, a function call almost always involves parentheses () immediately following a name.  
+
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+    //the expression movielength % 60 calculates the remainder when movieLength is divided by 60.
+    //this means this calculation 8784/60 = 146.4 but we are looking for the seconds
+    //we take the integer part 146 * 60 = 8760 - 8784 = 24 seconds remaining
+
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+    // Line 4 calculates the total number of whole minutes in the movie length.
+    // It subtracts the remaining seconds from the total movie length to get a value that is a multiple of 60,
+    // and then divides that value by 60 to convert it from seconds to minutes.
+    // So, it gives us the total number of complete minutes in the movie length.
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+    //result stores the variables of totalHours, remainingMinutes and remainingSeconds in a string format readable time clock "H:M:S"
+    //A better name for this variable could be MovieDuration
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+
+    //Yes, this code will work for all values of movieLength as it correctly calculates hours, minutes, and seconds 
+    //but if the movieLength is less than 5 seconds, will be 0:0:5, we need to use the padStart method to add leading zeros for better formatting.

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

@@ -1,20 +1,30 @@
+//declare a constant variable named penceString and assign it the string value "399p"
 const penceString = "399p";
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
 
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
-  0,
-  paddedPenceNumberString.length - 2
-);
+// here we remove the trailing 'p' from the string using the method substring() -1 of the total length
+console.log(penceStringWithoutTrailingP);
+
+
+//this line pads will contain a length of at least 3 characters, adding leading zeros if necessary
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");//399 or diff value -> 001
+
+// here we extract the pounds part of the string by taking all characters except the last two eg. 399 -> 3
+const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2); //3
+
+console.log(` this is the padStart adding 0 if its necessary ${paddedPenceNumberString}, and this here we just take the integer part ${pounds}`);
+
 
+// here we extract the pence part of the string by taking the last two characters eg. 399 -> 99
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
 
+  console.log(` this is the pence part we take the last two digits ${pence}`);
 console.log(`£${pounds}.${pence}`);
 
 // This program takes a string representing a price in pence

Sprint-1/4-stretch-explore/chrome.md

@@ -10,9 +10,86 @@ Let's try an example.
 In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
+    To invoke an alert that lives in the engine v8; we need to 
+    run `alert("Hello word")`
+
+
 What effect does calling the `alert` function have?
 
+    In short: alert() interrupts the page to show a message and waits for the user to acknowledge it.
+
+    📢 The message you pass to alert() is displayed to the user.
+
+    ⏸️ JavaScript execution pauses until the user clicks OK.
+
+    🚫 The user can’t interact with the page while the alert is open (it blocks the UI).
+
+
+
 Now try invoking the function `prompt` with a string input of `"What is your name?"` - store the return value of your call to `prompt` in an variable called `myName`.
 
+
+    let myName = prompt("What is your name");
+    alert("hi " + myName);
+
+    The prompt function displays a modal dialog that captures user input. The value entered is stored in myName, and alert then displays a greeting that includes the value stored in the variable myName.
+
+
 What effect does calling the `prompt` function have?
 What is the return value of `prompt`?
+
+    Calling the prompt() function displays a modal pop-up dialog that:
+
+    * Shows a message to the user
+
+    * Includes a text input field
+
+    * Has OK and Cancel      buttons
+
+    * Blocks interaction with the page until the user responds
+
+    If the user types something and clicks OK: It returns a String containing their text.
+
+If the user clicks OK without typing: It returns an empty string ("").
+
+If the user clicks Cancel or hits Esc: It returns null.
+
+
+
+
+# --- Browser Console Simulation ---
+
+> alert("hi " + myName);
+
+< undefined
+
+> let myName = prompt("What is your name")
+
+< undefined
+
+> console.log(myName)
+
+< null          // User clicked Cancel
+
+> let myName = prompt("What is your name")
+> console.log(myName)
+
+< "Kyle"          // User typed a name
+
+> let myName = prompt("What is your name")
+> console.log(myName)
+
+< ""            // User clicked OK without typing
+
+> console.log(typeof(myName))
+
+< "string"
+
+> console.log("Longitud:", myName.length);
+
+< Longitud: 0
+
+
+
+
+