diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js index 117bcb2b6..744ac8126 100644 --- a/Sprint-1/1-key-exercises/1-count.js +++ b/Sprint-1/1-key-exercises/1-count.js @@ -1,6 +1,12 @@ let count = 0; -count = count + 1; +// count = count + 1; +// count += 1; +count++; + +console.log(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 a statement or reassignment. It is changing the value associated with the 'count' variable. diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js index 47561f617..4a09edec5 100644 --- a/Sprint-1/1-key-exercises/2-initials.js +++ b/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 = `${firstName[0]}${middleName[0]}${lastName[0]}`; // https://www.google.com/search?q=get+first+character+of+string+mdn diff --git a/Sprint-1/1-key-exercises/3-paths.js b/Sprint-1/1-key-exercises/3-paths.js index ab90ebb28..620b2b227 100644 --- a/Sprint-1/1-key-exercises/3-paths.js +++ b/Sprint-1/1-key-exercises/3-paths.js @@ -9,7 +9,7 @@ // (All spaces in the "" line should be ignored. They are purely for formatting.) -const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt"; +const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt.json"; const lastSlashIndex = filePath.lastIndexOf("/"); const base = filePath.slice(lastSlashIndex + 1); console.log(`The base part of ${filePath} is ${base}`); @@ -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(1, lastSlashIndex); -// https://www.google.com/search?q=slice+mdn \ No newline at end of file +// const ext = filePath.slice(lastSlashIndex + 5); + +const ext = filePath.split('/').pop().split('.').pop(); + +// Although it is a lengthy solution but it works \ No newline at end of file diff --git a/Sprint-1/1-key-exercises/4-random.js b/Sprint-1/1-key-exercises/4-random.js index 292f83aab..ed7fe76bb 100644 --- a/Sprint-1/1-key-exercises/4-random.js +++ b/Sprint-1/1-key-exercises/4-random.js @@ -7,3 +7,9 @@ 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 + +// Math.random() * (maximum - minimum + 1) + minimum; +// Returns a random number between 1 and 100. +// The returned value is between 1 and 100 (both included); + +// Lastly, Math.floor() rounds down and returns the largest integer between 1 and 100 \ No newline at end of file diff --git a/Sprint-1/2-mandatory-errors/0.js b/Sprint-1/2-mandatory-errors/0.js index cf6c5039f..4ce0a54f4 100644 --- a/Sprint-1/2-mandatory-errors/0.js +++ b/Sprint-1/2-mandatory-errors/0.js @@ -1,2 +1,4 @@ -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? \ No newline at end of file +// 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 commented the above 2 lines so it won't run by the computer \ No newline at end of file diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js index 7a43cbea7..3bdb8d0a8 100644 --- a/Sprint-1/2-mandatory-errors/1.js +++ b/Sprint-1/2-mandatory-errors/1.js @@ -1,4 +1,6 @@ // trying to create an age variable and then reassign the value by 1 -const age = 33; +let age = 33; age = age + 1; + +// The value of 'let' variable can be reassigned not the value of 'const'; diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js index e09b89831..9278d091e 100644 --- a/Sprint-1/2-mandatory-errors/2.js +++ b/Sprint-1/2-mandatory-errors/2.js @@ -1,5 +1,7 @@ // 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}`); const cityOfBirth = "Bolton"; +console.log(`I was born in ${cityOfBirth}`); + +// The first first needs to be initialised then it will be accessed; diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js index ec101884d..ef21973ef 100644 --- a/Sprint-1/2-mandatory-errors/3.js +++ b/Sprint-1/2-mandatory-errors/3.js @@ -1,5 +1,9 @@ const cardNumber = 4533787178994213; -const last4Digits = cardNumber.slice(-4); +// const last4Digits = cardNumber.slice(-4); + +// slice() method cannot work on numbers. +// I changed the numbers to string and then implemented the slice() method +const last4Digits = cardNumber.toString().slice(-4); // The last4Digits variable should store the last 4 digits of cardNumber // However, the code isn't working diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js index 21dad8c5d..0db49507b 100644 --- a/Sprint-1/2-mandatory-errors/4.js +++ b/Sprint-1/2-mandatory-errors/4.js @@ -1,2 +1,6 @@ -const 12HourClockTime = "20:53"; -const 24hourClockTime = "08:53"; \ No newline at end of file +// const 12HourClockTime = "20:53"; +// const 24hourClockTime = "08:53"; + +// a variable name's first letter cannot start with a number +const twelveHourClockTime = "20:53"; +const twentyFourHourClockTime = "08:53"; \ No newline at end of file diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js index e24ecb8e1..f4745e6b4 100644 --- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js +++ b/Sprint-1/3-mandatory-interpret/1-percentage-change.js @@ -1,8 +1,9 @@ let carPrice = "10,000"; let priceAfterOneYear = "8,543"; -carPrice = Number(carPrice.replaceAll(",", "")); -priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," "")); +// I hope this RegExp is taht programming term +carPrice = Number(carPrice.replace(/,/g, "")); +priceAfterOneYear = Number(priceAfterOneYear.replace(/,/g, "")); const priceDifference = carPrice - priceAfterOneYear; const percentageChange = (priceDifference / carPrice) * 100; @@ -12,11 +13,20 @@ 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 + // There are 4 function calls. + // In line 4: Number() and replace(/,/g, "") are function calls. + // In line 5: Number() and replace(/,/g, "") are function calls. + // Including console.log(), there are 5 function calls. // 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? + // The syntax error was in line 5; a comma was missing // c) Identify all the lines that are variable reassignment statements + // Variable reassignment statements are in lines 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? + // First, it removes the digit group separator. // "10,000" => "10000" + // Then, the Number() method changes the string to a number. // "10000" => 10000 diff --git a/Sprint-1/3-mandatory-interpret/2-time-format.js b/Sprint-1/3-mandatory-interpret/2-time-format.js index 47d239558..175c1ee12 100644 --- a/Sprint-1/3-mandatory-interpret/2-time-format.js +++ b/Sprint-1/3-mandatory-interpret/2-time-format.js @@ -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? + // There are 6 variable declarations // b) How many function calls are there? + // There are no function calls except 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 + // 'movieLength % 60' finds out the remainder seconds which is 24 // d) Interpret line 4, what does the expression assigned to totalMinutes mean? + // It subtracts the remaining seconds from movieLength and finally divides by 60 to get the length in minutes // e) What do you think the variable result represents? Can you think of a better name for this variable? + // It stores the total movie length in HH:MM:SS format. + // I can name it totalRuntime; // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer + // Yes, the code works for all values. 6000 would be 1:40:0, for example diff --git a/Sprint-1/3-mandatory-interpret/3-to-pounds.js b/Sprint-1/3-mandatory-interpret/3-to-pounds.js index 60c9ace69..e928f1dc4 100644 --- a/Sprint-1/3-mandatory-interpret/3-to-pounds.js +++ b/Sprint-1/3-mandatory-interpret/3-to-pounds.js @@ -1,21 +1,32 @@ const penceString = "399p"; +// substring() method returns a portion of a string +// In the variable below, it returns "399" and penceString.length - 1 removes the last character ("p") const penceStringWithoutTrailingP = penceString.substring( 0, penceString.length - 1 ); +// Although pasStart() method does not seem necessary here, but this method gives a padding to a string from start +// so the "399" has a given length of 3 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); + +// substring() method returns a portion of a string +// In this case, it return only "3" which is the Pound +// and 'paddedPenceNumberString.length - 2' removes "99" which represents the pence const pounds = paddedPenceNumberString.substring( 0, paddedPenceNumberString.length - 2 ); +// substring() method removes "3" from "399" and returns "99"; +// padEnd() method pads the "99" and the padding applied is from the end of this string. const pence = paddedPenceNumberString - .substring(paddedPenceNumberString.length - 2) - .padEnd(2, "0"); + .substring(paddedPenceNumberString.length - 2); + -console.log(`£${pounds}.${pence}`); +// In the log, backticks are used to output template literals ${pounds} and ${pence} with added '£' sign. +// console.log(`£${pounds}.${pence}`); // This program takes a string representing a price in pence // The program then builds up a string representing the price in pounds @@ -25,3 +36,11 @@ console.log(`£${pounds}.${pence}`); // To begin, we can start with // 1. const penceString = "399p": initialises a string variable with the value "399p" + +// We don't need .padEnd(2, "0"); +// However, using this function will simplify and work for all types of pence +function toPounds(pence) { + return "£" + Number(pence.slice(0, -1) / 100).toFixed(2); +} + +console.log(toPounds("9p")); // £0.09 diff --git a/Sprint-1/4-stretch-explore/chrome.md b/Sprint-1/4-stretch-explore/chrome.md index e7dd5feaf..d0ff864b4 100644 --- a/Sprint-1/4-stretch-explore/chrome.md +++ b/Sprint-1/4-stretch-explore/chrome.md @@ -11,8 +11,13 @@ 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 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? +It opens a prompt asking for an input. + What is the return value of `prompt`? +The return value of `prompt` will be the output of whatever was written in the input of the prompt +If the input is empty, '' will be returned \ No newline at end of file diff --git a/Sprint-1/4-stretch-explore/objects.md b/Sprint-1/4-stretch-explore/objects.md index 0216dee56..6473158a7 100644 --- a/Sprint-1/4-stretch-explore/objects.md +++ b/Sprint-1/4-stretch-explore/objects.md @@ -5,12 +5,20 @@ 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? +Getting a function log(): ƒ log() { [native code] } Now enter just `console` in the Console, what output do you get back? +{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 stores a temporary log of system messages, including errors, warnings, and informational output + What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean? +`console.log` is a built-in function used to output messages or values in the console +`console.assert` is also a built-in function used for debugging that writes an error message if an error exists otherwise it does nothing. +`.` is maybe used to access the console. `console.log()` means access the 'log()' method inside 'console' object