London | 26-ITP-January | Khaliun Baatarkhuu | Sprint 1 | Coursework.

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

@@ -1,6 +1,7 @@
 let count = 0;
 
-count = count + 1;
+count = count + 1; 
+// line 3 is assigning the variable "count" a new value of "count +1", then storing it back into "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

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

@@ -5,7 +5,7 @@ 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 = ``;
+let initials = `${firstName.charAt(0)}${middleName.charAt(0)}${lastName.charAt(0)}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

@@ -12,12 +12,13 @@
 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 dir = filePath.slice(0,lastSlashIndex);
+const ext = filePath.slice(lastDotIndex+1);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

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

@@ -2,6 +2,11 @@ const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+//num can be any generated random number between 1 and 100, rounded down.
+
+
+
+
 
 // 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

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

@@ -1,2 +1,5 @@
-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?
+
+// I have erased the above two lines, to prevent the computer from running them. 

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

@@ -1,4 +1,4 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;

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

@@ -1,5 +1,8 @@
 // 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}`);
+//console.log(`I was born in ${cityOfBirth}`);
+//const cityOfBirth = "Bolton";
+
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,5 +1,13 @@
+//const cardNumber = 4533787178994213;
+//const last4Digits = cardNumber.slice(-4);
+
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = String(cardNumber).slice(-4);
+
+//My prediction was the long card number isn't a string so js will assume it's a variable
+//Error given: cardNumber.slice is not a function
+//added String function
+
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working

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

@@ -1,2 +1,7 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+//const 12HourClockTime = "20:53";
+//const 24hourClockTime = "08:53";
+
+const twentyFourHourClockTime = "20:53";
+const twelveHourClockTime = "08:53";
+
+//variable names in js cannot start with numbers

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

@@ -1,8 +1,8 @@
 let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
-carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+carPrice = Number(carPrice.replaceAll(",",""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",",""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -13,10 +13,27 @@ 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 three function calls: replaceAll() - used twice, number() - used twice, console.log() - used once.  
+// carPrice = Number(carPrice.replaceAll("," , ""));
+// priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," , ""));
+// console.log(`The percentage change is ${percentageChange}`);
+
 // 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?
 
+//There was a syntax error on line five, missing comma. Fixed by adding one.
+
 // c) Identify all the lines that are variable reassignment statements
 
+//carPrice = Number(carPrice.replaceAll("," , ""));
+//priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," , ""));
+
 // d) Identify all the lines that are variable declarations
 
+//let carPrice = "10,000";
+//let priceAfterOneYear = "8,543";
+//const priceDifference = carPrice - priceAfterOneYear;
+//const percentageChange = (priceDifference / carPrice) * 100;
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+// It's removing the commas, since javascript will recognise 10,000 as a string not a number.

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

@@ -13,13 +13,26 @@ console.log(result);
 
 // a) How many variable declarations are there in this program?
 
+// There are six, all six lines of code use const as a variable declaration. 
+
 // b) How many function calls are there?
 
+//There is only one funsction call, 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
 
+// It represents how many seconds remain, before converting them to minutes first. 
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+// it represents the movie length converted to minutes, without the remaining seconds. 
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+//It represents the film length in a time string format. Better alternative could be formattedDuration, as it is self-explanatory,
+//as opposed to generic 'result'.
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// I have tried values between 0-9, ie all positive/whole numbers, and it works. However there is no input validation, ie negative numbersm, non-integers etc, so it won't work properly there.  

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

@@ -1,27 +1,27 @@
 const penceString = "399p";
-
+// 1. const penceString = "399p": initialises a string variable with the value "399p"
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
-
+//2. Removes the trailing "p" from the pencestring, leaving 399 as the new value.
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+//3. This line ensures there are three characters, at least, by adding "0" to the start if necessary.  
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
-
+//4. We are extracting the pounds now, ie the first character. 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
-
+//4. Here, we are extracting the last two digits, ie pence. Padend insures there are two digits and adds a "0" to compensate, if necessary.
 console.log(`£${pounds}.${pence}`);
+//5. Here it should show the final result of £3.99
+
 
 // This program takes a string representing a price in pence
 // The program then builds up a string representing the price in pounds
 
 // You need to do a step-by-step breakdown of each line in this program
 // Try and describe the purpose / rationale behind each step
-
-// To begin, we can start with
-// 1. const penceString = "399p": initialises a string variable with the value "399p"

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

@@ -12,7 +12,16 @@ invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
 
+1. This function displays a pop-up box with Hello world written on it, with on OK button.  
+
 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`.
 
 What effect does calling the `prompt` function have?
+
+2. It displays a pop-up box with What's your name written on it and an empty dialog box inside, awaiting my input.
+Also, there are two options of OK and Cancel. 
+
 What is the return value of `prompt`?
+
+3. If I enter my name undefined appears, same if i press the cancel button. Fixed this by adding myName at the end.
+Now the value when i enter my name shows "my name", if i press cancel it shows "null".

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

@@ -6,11 +6,28 @@ Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
 
+1. I got back, 'ƒ log() { [native code] }'
+which is the definition of console function. 
+
 Now enter just `console` in the Console, what output do you get back?
 
+2. I got back, console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
+Which is the definition of console as an object with several examples of functions after the object. 
+
 Try also entering `typeof console`
 
+3. I've got 'object', it is showing me that console itself is an object. 
+
 Answer the following questions:
 
 What does `console` store?
+
+4. The object console stores different functions used for various purposes, such as debugging, showing errors etc.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+5. console.log allows you access the log property of the console object. ie log is a property stored inside the object. In this case log as a function.
+
+console.assert - assert is another function stored inside console object, used for checking is a condition is true. 
+
+"." means go inside this property and get the property provided. Perfect example of this is, "person" is an object, "name" is a  property and so "." allows me to access the property.