London | 26-ITP-Sep | Rawan Almutairi | Sprint 2 | JavaScript exercises

[Rawan0-0]

Self checklist

• I have titled my PR with Region | Cohort | FirstName LastName | Sprint | Assignment Title
• My changes meet the requirements of the task
• I have tested my changes
• My changes follow the style guide

Task code

CYF-1039

Changelist

Sprint 2 work

Questions

No questions

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[iscmiguelsamaniego]

Fantastic work! Your technical grasp, attention to edge cases (like octal numbers), and step-by-step code breakdowns are spot-on.

Keep up this meticulous approach—you are making brilliant progress!

[iscmiguelsamaniego]

Great job! You correctly identified how the variable is initialized and reassigned.

Quick question: How would you specifically describe the role of the = sign in that second line?

[Rawan0-0]

//Line two we see the variable count using the = sign to assign a new value whcih is count previous value + 1
//the equal sign in line two is assigned operator that stores the new value to the variable

[iscmiguelsamaniego]

Great job! This is a very clean and clever solution using template literals and bracket notation.

Quick question: Is there another built-in string method besides bracket notation you could use to get the first character?

[Rawan0-0]

string.prototype.replace()

[iscmiguelsamaniego]

Spot-on implementation for extracting dir and ext! To polish your code, you can make the comments a bit more direct and concise.

Quick question: When using filePath.slice(0, lastSlashIndex) for dir, why do we include 0 as the starting index, and what happens if you omit it?

[Rawan0-0]

If we omit the first index, the string won't break but will go to the wrong location; in the case of omitting the 0 index, it will delete anything before the last index ''/'

[iscmiguelsamaniego]

Clear breakdown of the math logic!

Just remember the order: Math.random() runs first to generate a decimal, then the math scales it, and finally Math.floor() rounds it down.

Quick question: What purpose does the + 1 serve inside (maximum - minimum + 1)?

[Rawan0-0]

I had to search for this one to understand it. Math.random() generates a decimal that ranges between the values 0 and 0.99999, so when we try to scale it up Math.random() will generate values between 0 and 8.9999, so it doesn't include 9. This becomes an issue when we use Math.floor as it will round it to the nearest whole number, and because it doesn't include the number 9, it will round down from 0 to 8.

[iscmiguelsamaniego]

Spot-on distinction between const and let for handling variable updates.

Quick question: Is there a shorthand assignment operator you could use instead of writing age = age + 1?

[Rawan0-0]

yes, +=

[iscmiguelsamaniego]

Not quite a ReferenceError here—cardNumber is actually declared, but because it's a number rather than a string, JavaScript throws a TypeError because .slice() isn't a valid method for numbers.

Quick question: What method can you call on cardNumber to convert it into a string first so .slice(-4) will work?

[Rawan0-0]

toString()

[iscmiguelsamaniego]

Spot-on explanation! Variable names cannot start with numbers.

Quick question: While starting with a capital letter works syntactically, what is the standard JavaScript naming convention (case style) usually used for variables made of multiple words like this?

[Rawan0-0]

camelCase

[iscmiguelsamaniego]

Spot-on answers! Your breakdown of line 5's syntax error, reassignments, and the purpose of replaceAll() is completely accurate.

Quick question: Why is replaceAll() a better choice here than a standard replace() method?

[Rawan0-0]

replaceAll includes all the specified characters and changes them, unlike replace(), which searches for the character but stops once it is found.

[iscmiguelsamaniego]

Spot-on analysis! Your observation about leading zeros triggering an octal syntax error is a brilliant and advanced catch.

Quick question: If remainingSeconds is 5, the output currently shows ...:5 instead of ...:05. How might you ensure single-digit numbers always display with two digits?

[Rawan0-0]

Since the digit zero is before the 5. We create a numerical string, then convert the string to a numerical value or add the zero digit as a string before the number or we modify the function to include strings so we can manipulate the numbers.

[iscmiguelsamaniego]

Great step-by-step breakdown! You clearly traced how substring, padStart, and padEnd work together to parse and format the price string correctly.

Quick question: Why is padStart(3, "0") particularly important if someone inputs a smaller value like "9p" instead of "399p"?

[Rawan0-0]

It specify the starting values so we don't have random numbers that could cause a bug in the program. We restrict it.

[Rawan0-0]

Fantastic work! Your technical grasp, attention to edge cases (like octal numbers), and step-by-step code breakdowns are spot-on.

Keep up this meticulous approach—you are making brilliant progress!

Thank you so much for this wonderful feedback. I certainly will check each one and submit my work for each one. It was really good to hear that I did a good job; I was really worried I might have made some mistakes.

[abdishakoor-dev]

Rawan, you've answered every question, and some of the hardest parts are right: dir and ext in 3-paths.js work for any file name, and your fixes in 1.js and 4.js run. I ran each file with node, and a few answers need another go before this can be marked Complete. I've left a step-by-step hint on each one.

How to run a file: in VS Code, right-click the folder (for example 2-mandatory-errors), choose Open in Integrated Terminal, then type node 3.js and press Enter. Run each file after you change it.

What to do:

1. 3-to-pounds.js: delete the copied code on lines 48 to 53 so the file runs again, then add the value to each step (hints on lines 44 and 49).
2. 2.js: change the order of the code so it prints I was born in Bolton (line 4).
3. 3.js: fix line 2 and change ReferenceError to TypeError (line 10).
4. 1.js, 2.js, 3.js, 4.js: copy the error message node prints into each file (line 6 of 1.js shows how).
5. 4-random.js: fix "nearest" on line 22 and say what num is.
6. 2-time-format.js: redo c), d) and f) (lines 22 and 26).
7. 1-percentage-change.js e): say what Number(...) does (line 24).
8. Delete lines that start with // and contain old code: 3-paths.js lines 12-15, 21-22, 35, 37, 39, plus your notes on lines 29 and 60; 2-initials.js line 8; 4.js lines 5-6 (after you've copied its error message).
9. Format each file: right-click inside the file, choose Format Document, then save. Do this for all 12 files.

Once these are pushed, I expect to mark this Complete. Add the Needs Review label again when you have pushed.

[abdishakoor-dev]

Lines 49 to 53 are copies of the program's own code (lines 14 to 18), so const pence is now created twice. Node refuses to run the file: SyntaxError: Identifier 'pence' has already been declared.

Delete lines 48 to 53, then run node 3-to-pounds.js. You should see £3.99 printed once. Your explanation should only be // comments; the program itself stays exactly as it was given.

[abdishakoor-dev]

Your steps say which method is used, but not what it gives. Write the value each line produces for "399p". Here is step 2 as an example:

// 2. penceString.length is 4, so penceString.length - 1 is 3.
//    substring(0, 3) keeps characters 0, 1 and 2, giving "399" (the p is removed).

Now do the same for the rest, filling in the ...:

// 3. padStart(3, "0") gives "..."
// 4. pounds is "..."
// 5. pence is "..."
// 6. the console.log prints ...

Then change line 1 to "9p", run it, and write down what it prints. What did padStart do to "9"? Change line 1 back to "399p" afterwards.

[abdishakoor-dev]

Your explanation on line 7 is right. JavaScript runs the file from top to bottom, and line 4 uses cityOfBirth before line 5 has created it.

So what order should these two lines be in? Change it, run node 2.js, and you should see I was born in Bolton.

[abdishakoor-dev]

This one isn't a ReferenceError. Run the file and look at the last line of the error: node says TypeError: cardNumber.slice is not a function. cardNumber is there (line 1), but it holds a number, and .slice() only works on strings.

1. In your thread reply you found toString(). Put it between cardNumber and .slice(-4) on line 2. Add console.log(last4Digits); underneath and run it: you should see 4213.
2. Replace line 10 with three comments in your own words:

// Prediction: ...
// Error: TypeError: cardNumber.slice is not a function
// Why: ...

[abdishakoor-dev]

Your fix is right. This section also wants the error message node gives for the original code. To see it:

1. Change let back to const on line 3 and run node 1.js.
2. Copy the line that starts with TypeError into a comment here.
3. Change const back to let.

Do the same in 4.js (remove the // from line 5 for a moment), and in 2.js and 3.js before you fix them. Each file should end up with the error message and your explanation.

[abdishakoor-dev]

Two things here.

1. Math.floor always rounds down, as you said on line 21. Math.floor(4.9) is 4, not 5. Change "nearest" on line 22.
2. The question asks what num represents. Add console.log(num); after line 4 and run the file ten times. Then finish with one line:

// So num is a random whole number from ... to ...

Your thread reply already explains why the + 1 is there, so you can copy that in too.

[abdishakoor-dev]

c) and d) need the numbers from this program. Add these two lines after line 4 and run the file:

console.log(remainingSeconds);
console.log(totalMinutes);

Then fill in:

// c) movieLength % 60 is ..., which is the seconds left over after ...
// d) totalMinutes is ..., the number of whole minutes. Line 4 takes away remainingSeconds first so that ...

Delete the two console.log lines afterwards.

[abdishakoor-dev]

const movieLength = 08784; actually runs and prints 2:26:24, because 8 isn't an octal digit, so JavaScript reads it as a normal number. So this answer needs changing.

Change line 1 to each of these, run the file, and write down what it prints: 59, 3605, -100, 90.5. Would you show 0:0:59 to someone as a time? What would you expect it to look like instead? Write one sentence for each value that doesn't look right. Put line 1 back to 8784 afterwards.

[abdishakoor-dev]

You've explained replaceAll. Now Number(...). Add these two lines and run the file:

console.log(typeof carPrice); // put this before line 4
console.log(typeof carPrice); // put this after line 4

What changes? Write one sentence about what Number(...) did, and why line 7 needs it before subtracting. Then delete the two lines.