London | 26-ITP-SEP | Bartosz Kawiak | Sprint 2 | Course-work-2

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

@@ -2,5 +2,7 @@ let count = 0;
 
 count = count + 1;
 
+// = is an assign operator so if count = 0 at line 1 then at line 3 count = 0 + 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

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

@@ -5,6 +5,10 @@ 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);
+
+console.log(initials);
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

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

@@ -17,7 +17,10 @@ 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(-4);
 
-// https://www.google.com/search?q=slice+mdn
+console.log(dir);
+console.log(ext);
+
+// https://www.google.com/search?q=slice+mdn

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

@@ -2,6 +2,10 @@ const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+//Math.floor is rounding down number from float number to integer
+//Math.random create a random decimal number(float) from 0 up to 1 we then multiply it by (100) and add 1(minimum)
+// variable num represents a random integer ranging from 1 to 100
+console.log(num);
 
 // 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-2/2-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?
+We don't want the computer to run these 2 lines - how can we solve this problem?
+
+//We have to use the // to comment a single line
+/* or use /* to comment multiple lines */ 

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

@@ -2,3 +2,5 @@
 
 const age = 33;
 age = age + 1;
+/* const means that the variable cannot be reassigned we should use let keyword instead.
+TypeError displayed due to that. */

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

@@ -3,3 +3,8 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+//The error we see it's a ReferenceError which tells us that we cannot access variable before initialization.
+
+/*JavaScript reads the code from top to bottom, order is wrong.
+Task cannot be executed as variable cannot be access before being created. */

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

@@ -1,9 +1,14 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
+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
+
+/*The code would not work because cardNumber variable stores number data type and .slice() method cannot be used on a number,
+if we run the code without changing data type to string we will get TypeError displayed
+I used .toString() method to convert cardNumber variable to a string and then used .slice(-4) to get the last 4 digits. */

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

@@ -1,2 +1,4 @@
 const 12HourClockTime = "8:53pm";
 const 24hourClockTime = "20:53";
+
+//A variable cannot start with a number, SyntaxError is displayed.

Sprint-2/3-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;
@@ -20,3 +20,10 @@ console.log(`The percentage change is ${percentageChange}`);
 // d) Identify all the lines that are variable declarations
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+//a)There are 5 function calls on line 4, 5 and 10.
+//b) error is coming from line 5, there is missing , between arguments in replaceAll method
+//c) line 4 and 5
+//d) line 1,2 and 7,8
+/*e) replaceAll method inside of () replace comma with nothing, removing it from the string,
+then Number converts string to number data type  */

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = -8784.08; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -23,3 +23,10 @@ console.log(result);
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+//a) There are 6 variable declarations.
+//b)There is 1 function call on line 10
+//c) movieLength use remainder operator % . movieLength % 60 returns the remaining seconds after dividing the movie length into full minutes.
+//d) expression assigned to totalMinutes calculate movie time in whole minutes.
+//e) This variable represent total movie time in hh/mm/ss format, we could name it totalTime or totalMovieTime.
+//f) Yes, the code works correctly when movieLength is non-negative whole number that represents seconds.

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
@@ -24,4 +24,18 @@ console.log(`£${pounds}.${pence}`);
 // 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"
+// 3. penceStringWithoutTrailingP is created using substring() on penceString. The purpose is to remove the trailing "p"..
+// 4. value for substring method to start from which is beginning of the string.
+// 5. penceString variable uses argument of .length to -1 (p) from the value, 399p becomes 399.
+// 6. substring method closure
+// 8. paddedPenceNumberString uses padStart() to make the string at least 3 characters long, adding "0" at the beginning when needed.
+// 9. pounds variable assigns paddedPenceNumberString that uses substring method which returns part of the string from the start of index.
+//10. value for substring method which is beginning of the string.
+//11. paddedPenceNumberString variable is using length argument and deduct 2 out of length of the string 399 become 3 as pounds.
+//12. Closes the substring method.
+//14. pence variable created from  paddedPenceNumberString
+//15. substring method called which value of is in the parenthesis (variable length -2 characters)
+//16. method padEnd is called that contains at least 2 character and adds 0 at the end if needed.
+//18. we log £3.99 in the console.

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

@@ -9,7 +9,15 @@ In the Chrome console, invoke the function `alert` with one argument, the string
 
 What effect does calling the `alert` function have?
 
+### Alert would display a pop up window which can be used to display for example error messages.
+
 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?");
+
 What effect does calling the `prompt` function have?
 What is the return value of `prompt`?
+
+### Prompt display text input option that we can store in a variable.
+
+### prompt returns text that user entered in the input field

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

@@ -6,11 +6,22 @@ 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?
 
+### the output is console object with it's available properties and methods.
+
 Try also entering `typeof console`
 
+### console is an object
+
 Answer the following questions:
 
 What does `console` store?
+
+### Console store functions that can interact with the console object
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+### "." is used to access a property or method inside an object eg. console.log access the log function where .assert access the assert function

Sprint-2/README.md

@@ -12,7 +12,7 @@ This README will guide you through the different sections for this week.
 
 ## 1 Exercises
 
-In this section, you'll have a short program and task. Some of the syntax may be unfamiliar - in this case, you'll need to look things up in documentation. 
+In this section, you'll have a short program and task. Some of the syntax may be unfamiliar - in this case, you'll need to look things up in documentation.
 
 https://developer.mozilla.org/en-US/docs/Web/JavaScript
 
@@ -28,7 +28,7 @@ You must use documentation to make sense of anything unfamiliar - learning how t
 
 You can also use `console.log` to check the value of different variables in the code.
 
-https://developer.mozilla.org/en-US/docs/Web/JavaScript 
+https://developer.mozilla.org/en-US/docs/Web/JavaScript
 
 ## 4 Explore - Stretch 💪