London | ITP-Jan-26 | Mohsen Zamani | Sprint 1 | Coursework

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

@@ -4,3 +4,6 @@ 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
+
+// Line 3 is adding 1 to the variable count and assign it again to count using =.
+// So after line 3 the value of count is 1.

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

@@ -5,7 +5,6 @@ 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 = `${firstName[0]}${middleName[0]}${lastName[0]}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
-

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

@@ -17,7 +17,9 @@ 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 = base.split(".")[1];
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn
+console.log(dir);
+console.log(ext);

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

@@ -7,3 +7,8 @@ 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
+
+console.log(num);
+
+// num is a random number between 1 and 100(inclusive)
+// using Math.random which returns a number between 0(inclusive) and 1(exclusive)

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?
+
+// running the code throws error because it is written in human language for human understanding
+// so it must be commented

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

@@ -2,3 +2,7 @@
 
 const age = 33;
 age = age + 1;
+
+// TypeError: Assignment to constant variable.
+// JS throws above error because the variable age is declared as a constant
+// and can not be reassigned.

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

@@ -3,3 +3,6 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+// cityOfBirth is declared before initialization
+// so JS can not access it

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

@@ -1,4 +1,4 @@
-const cardNumber = 4533787178994213;
+const cardNumber = "4533787178994213";
 const last4Digits = cardNumber.slice(-4);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
@@ -7,3 +7,9 @@ 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
+
+// the code will throw error because slice is a string method
+// and not a Number method
+
+// TypeError: cardNumber.slice is not a function
+// my prediction was correct

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

@@ -1,2 +1,4 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";
+
+// Variable names can not start with numbers

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;
@@ -12,11 +12,16 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+// 5 times  (called on lines: 4, 4, 5, 5, 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. It is a syntaxError. string.replaceAll() is missing a ','
 
 // c) Identify all the lines that are variable reassignment statements
+// 4, 5
 
 // d) Identify all the lines that are variable declarations
+// 1, 2, 7, 8
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// It is replacing all "," with ""(empty string) and turn it into a number data type

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 8784536346344.633; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -12,14 +12,21 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
+// 6
 
 // b) How many function calls are there?
+// 1
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// Divides movieLength by 60 and returns the remaining and assigns it to remainingSeconds
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// It is deducting remainingSeconds from movieLength(also in seconds) and divide the result by 60, so it turns into minutes
+// and finally assign it to totalMinutes
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// The duration of movie, it can be renamed to movieDuration
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// With float numbers, it seems to need a rounding because the result seems ugly: 2:-26:-24.63299999999981

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

@@ -25,3 +25,10 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 2. Using the String.substring method, cuts the trailing p out of the string
+// 3. Using String.padStart method, makes the penceStringWithoutTrailingP to length of 3
+// by adding 0 to the left, if it is not length of 3
+// 4. Takes the first character of paddedPenceNumberString and assigns it to pounds
+// 5. Takes from position 1 of paddedPenceNumberString to the end and makes it the length of 2
+// by adding 0 to the end and assigns it to pence
+// 6. Prints the calculates pounds and pence

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

@@ -11,8 +11,11 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+It opens an alert window in Chrome saying "Hello world!"
 
 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?
+Opens an alert window, but waits for an input
 What is the return value of `prompt`?
+The name typed by user

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

@@ -5,12 +5,17 @@ In this activity, we'll explore some additional concepts that you'll encounter i
 Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
+ƒ log() { [native code] }
 
 Now enter just `console` in the Console, what output do you get back?
+console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
 Try also entering `typeof console`
+'object'
 
 Answer the following questions:
 
 What does `console` store?
+It is an object, and includes some variables and functions called methods.
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+'.' helps to access the proberties of console object.