London | 26-ITP-Sep | Mahir Shah | Sprint 2 | Sprint 2 Coursework

Sprint-2/1-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
+
+//Updating the value of count by adding 1 to it's current value. = is assigning

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

@@ -5,6 +5,6 @@ const 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.
 
-const initials = ``;
+const initials = `firstName.charAt(0) + middleName.charAt(0) + lastName.charAt(0)`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

Sprint-2/1-key-exercises/3-paths.js

@@ -17,7 +17,8 @@ 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, filePath.indexOf(base));
+const ext = filePath.slice(-(filePath.length - filePath.indexOf(".")));
+console.log(ext);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

Sprint-2/1-key-exercises/4-random.js

@@ -7,3 +7,12 @@ 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
+
+//num is a random, rounded down number between 100 and 1.
+//math.floor rounds down.
+//math.random gives a random number between 0 and 1. It can be equal to 0, but not equal to 1,
+//(maximum - minimum + 1) gives in this case 100
+//So then Math.random() * (maximum - minimum + 1) gives a number between 0 and 99
+//Math.random() * (maximum - minimum + 1) gives a number between 1 and 100
+//and thus Math.floor(Math.random() * (maximum - minimum + 1)) + minimum; gives a whole rounded
+//down number

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

@@ -1,2 +1,3 @@
-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?
+//Make it code

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

@@ -2,3 +2,8 @@
 
 const age = 33;
 age = age + 1;
+
+//TypeError: Assignment to constant variable.
+//Age is constant so can't be reassigned
+//To fix, change const to let, so line 3 becomes:
+//let age = 33;

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

@@ -3,3 +3,7 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+//ReferenceError: Cannot access 'cityOfBirth' before initialization
+//Trying to use cityOfBirth before it's defined
+//To fix, put line 5 before line 4, so it is initialised before use

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

@@ -1,9 +1,13 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber % 10000;
+console.log(last4Digits);
 
 // 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
+
+//TypeError: cardNumber.slice is not a function
+//cardNumber is an integer, and slice is a string method, so slice doesn't work on cardNumber

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

@@ -1,2 +1,6 @@
 const 12HourClockTime = "8:53pm";
 const 24hourClockTime = "20:53";
+
+//SyntaxError: Invalid or unexpected token
+//In javascript, variable names cannot start with a number.
+//To fix, either put number at the end or start with _

Sprint-2/3-mandatory-interpret/1-percentage-change.js

@@ -12,11 +12,17 @@ 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 function calls. 2 in line 7, 2 in line 8, 1 in line 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?
+//Error is from line 5, no comma separating arguments for replace all. fix by adding comma after ","
 
 // c) Identify all the lines that are variable reassignment statements
+//4 and 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?
+//takes the string 10,000 and replaces all the commas with empty string, effectively removing the comma
+//makes the string into number format so it can be converted to a number

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 5; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -12,14 +12,24 @@ 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?
+//5
 
 // 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
+//% is the modulo operator, which gives the remainder after operand.
+//so in this case, the remainder of movieLength/60,
+// the number of seconds not in a whole minute
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+//Take the total number of seconds in the move, minus the remainder of movieLength/60 to give
+//a number that divides exactly by 60, then divide that number by 60. it converts the
+// time into minutes
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+//The number of whole minutes in the movie. numFullMinutes
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+//Yes the math is fine and works with all numbers.

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

@@ -2,13 +2,13 @@ const penceString = "399p";
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
-  penceString.length - 1
+  penceString.length - 1,
 );
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
 const pounds = paddedPenceNumberString.substring(
   0,
-  paddedPenceNumberString.length - 2
+  paddedPenceNumberString.length - 2,
 );
 
 const pence = paddedPenceNumberString
@@ -25,3 +25,29 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(
+//  0,
+//  penceString.length - 1
+//);
+// finds a substring starting at 0 index to 1 before the last index, and assigns the
+// substring to penceStringWithoutTrailingP. This removes the p and leaves us with just
+// the number
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+// Makes it so that the string is always at least 3 characters, by adding leading 0 until
+// it is 3 characters long.
+
+// 4. const pounds = paddedPenceNumberString.substring(
+//  0,
+//  paddedPenceNumberString.length - 2,
+//);
+// Finds the substring of number paddedPenceNumberString, with the last 2 digits cut off
+// basically finds the number of pounds by cutting off the pence
+
+// 5. const pence = paddedPenceNumberString
+//  .substring(paddedPenceNumberString.length - 2)
+//  .padEnd(2, "0");
+// Takes the substring starting at the total length-2, to the end. Essentially taking the
+// last 2 digits
+// Then adds 0 to the beginning so it is at least 2 characters long

Sprint-2/4-stretch-explore/chrome.md

@@ -8,8 +8,12 @@ Let's try an example.
 In the Chrome console, invoke the function `alert` with one argument, the string `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+Message window at the top, that takes over the window with the message of the argument
 
 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?
 What is the return value of `prompt`?
+
+prompt creates a window at the top with a text input box, with the message passed as the argument
+the return value is whatever was written in the box

Sprint-2/4-stretch-explore/objects.md

@@ -5,12 +5,98 @@ 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] }, which is telling me what it is, a function
 
 Now enter just `console` in the Console, what output do you get back?
+assert
+: 
+ƒ assert()
+clear
+: 
+ƒ clear()
+context
+: 
+ƒ context()
+count
+: 
+ƒ count()
+countReset
+: 
+ƒ countReset()
+createTask
+: 
+ƒ createTask()
+debug
+: 
+ƒ debug()
+dir
+: 
+ƒ dir()
+dirxml
+: 
+ƒ dirxml()
+error
+: 
+ƒ error()
+group
+: 
+ƒ group()
+groupCollapsed
+: 
+ƒ groupCollapsed()
+groupEnd
+: 
+ƒ groupEnd()
+info
+: 
+ƒ info()
+log
+: 
+ƒ log()
+memory
+: 
+MemoryInfo {totalJSHeapSize: 13400000, usedJSHeapSize: 11200000, jsHeapSizeLimit: 3760000000}
+profile
+: 
+ƒ profile()
+profileEnd
+: 
+ƒ profileEnd()
+table
+: 
+ƒ table()
+time
+: 
+ƒ time()
+timeEnd
+: 
+ƒ timeEnd()
+timeLog
+: 
+ƒ timeLog()
+timeStamp
+: 
+ƒ timeStamp()
+trace
+: 
+ƒ trace()
+warn
+: 
+ƒ warn()
+Symbol(Symbol.toStringTag)
+: 
+"console"
+[[Prototype]]
+: 
+Object
+which is a list of methods in console
 
 Try also entering `typeof console`
 
 Answer the following questions:
 
 What does `console` store?
+methods to interact with the console
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+it means, from the object console, access the function log or assert. 
+the fullstop is the connector to access the methods