diff --git a/Sprint-1/1-key-exercises/1-count.js b/Sprint-1/1-key-exercises/1-count.js index 117bcb2b6e..4d60780f1f 100644 --- a/Sprint-1/1-key-exercises/1-count.js +++ b/Sprint-1/1-key-exercises/1-count.js @@ -4,3 +4,9 @@ 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 updating the value of the count variable. + The = operator is an assignment operator that takes the value on the right side (count + 1) + and assigns it to the variable on the left side (count). + This means that the current value of count is increased by 1, and then that new value is stored back into the count variable. + The same effect could be achieved with the shorthand operator `count += 1`, or even better with `count++` which increments the value of count by 1. +*/ \ No newline at end of file diff --git a/Sprint-1/1-key-exercises/2-initials.js b/Sprint-1/1-key-exercises/2-initials.js index 47561f6175..6ef71d66cc 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 - +console.log(initials); diff --git a/Sprint-1/1-key-exercises/3-paths.js b/Sprint-1/1-key-exercises/3-paths.js index ab90ebb28e..73ba859dcf 100644 --- a/Sprint-1/1-key-exercises/3-paths.js +++ b/Sprint-1/1-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, lastSlashIndex); +const ext = filePath.slice(filePath.lastIndexOf(".")); +console.log(`The dir part of ${filePath} is ${dir}`); +console.log(`The ext part of ${filePath} is ${ext}`); // https://www.google.com/search?q=slice+mdn \ 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 292f83aabb..d4dec2db1a 100644 --- a/Sprint-1/1-key-exercises/4-random.js +++ b/Sprint-1/1-key-exercises/4-random.js @@ -7,3 +7,6 @@ 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 integer between the minimum and maximum values (inclusive), that is, a value between 1 and 100 (inclusive). \ 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 cf6c5039f7..044add7ac1 100644 --- a/Sprint-1/2-mandatory-errors/0.js +++ b/Sprint-1/2-mandatory-errors/0.js @@ -1,2 +1,2 @@ -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? diff --git a/Sprint-1/2-mandatory-errors/1.js b/Sprint-1/2-mandatory-errors/1.js index 7a43cbea76..6ef2ea9792 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; + +console.log(age); diff --git a/Sprint-1/2-mandatory-errors/2.js b/Sprint-1/2-mandatory-errors/2.js index e09b89831d..11f669a295 100644 --- a/Sprint-1/2-mandatory-errors/2.js +++ b/Sprint-1/2-mandatory-errors/2.js @@ -1,5 +1,5 @@ // Currently trying to print the string "I was born in Bolton" but it isn't working... // what's the error ? +const cityOfBirth = "Bolton"; // cityOfBirth wasn't declared and given a value before the console.log console.log(`I was born in ${cityOfBirth}`); -const cityOfBirth = "Bolton"; diff --git a/Sprint-1/2-mandatory-errors/3.js b/Sprint-1/2-mandatory-errors/3.js index ec101884db..86571adbe6 100644 --- a/Sprint-1/2-mandatory-errors/3.js +++ b/Sprint-1/2-mandatory-errors/3.js @@ -1,5 +1,7 @@ const cardNumber = 4533787178994213; -const last4Digits = cardNumber.slice(-4); +const last4Digits = Number(String(cardNumber).slice(-4)); + +console.log(last4Digits); // The last4Digits variable should store the last 4 digits of cardNumber // However, the code isn't working @@ -7,3 +9,8 @@ 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 + +// Slice method can be used on strings and arrays, not on numbers. +// The error message is telling that slice is not a function, but this happens because number don't have a slice method. +// I have used String(cardNumber) to convert the number to a string, so that the slice method can be used on it. +// Then the 4 digit string is converted back to a number with Number(string) to match the expected type. diff --git a/Sprint-1/2-mandatory-errors/4.js b/Sprint-1/2-mandatory-errors/4.js index 5f86c730bc..52a31c9784 100644 --- a/Sprint-1/2-mandatory-errors/4.js +++ b/Sprint-1/2-mandatory-errors/4.js @@ -1,2 +1,10 @@ -const 12HourClockTime = "8:53pm"; -const 24hourClockTime = "20:53"; +const twelveHourClockTime = "8:53pm"; +const twentyFourHourClockTime = "20:53"; + +console.log(twelveHourClockTime); +console.log(twentyFourHourClockTime); + +// The code wasn't working because of the original variable names that were starting with a number. +// So, I renamed the variables: +// 12HourClockTime to twelveHourClockTime +// 24HourClockTime to twentyFourHourClockTime diff --git a/Sprint-1/3-mandatory-interpret/1-percentage-change.js b/Sprint-1/3-mandatory-interpret/1-percentage-change.js index e24ecb8e18..0dd8af156c 100644 --- a/Sprint-1/3-mandatory-interpret/1-percentage-change.js +++ b/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 +12,19 @@ console.log(`The percentage change is ${percentageChange}`); // Read the code and then answer the questions below // a) How many function calls are there in this file? Write down all the lines where a function call is made +// There are 5 function calls in this file: +// Lines 4 and 5 - replaceAll function call +// Lines 4 and 5 - Number function call +// Line 10 - console.log function call // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem? +// Line 5 had an error because there was a missing comma between "," and "" in replaceAll function call. - SyntaxError // c) Identify all the lines that are variable reassignment statements +// Lines 4 and 5 are variable reassignment statements for carPrice and priceAfterOneYear. // d) Identify all the lines that are variable declarations - +// Lines 1, 2, 7 and 8 are variable declarations for carPrice, priceAfterOneYear, priceDifference and percentageChange. // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression? +// replaceAll function is used to replace all the occurrences of a character in a string. +// The expression Number() is converting the string carPrice, that was pruned of the comma, to a number. diff --git a/Sprint-1/3-mandatory-interpret/2-time-format.js b/Sprint-1/3-mandatory-interpret/2-time-format.js index 47d2395587..d9cb77b8e4 100644 --- a/Sprint-1/3-mandatory-interpret/2-time-format.js +++ b/Sprint-1/3-mandatory-interpret/2-time-format.js @@ -9,17 +9,46 @@ const totalHours = (totalMinutes - remainingMinutes) / 60; const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`; console.log(result); +// testing different cases +function movieLengthFormatter(movieLength) { + const remainingSeconds = movieLength % 60; + const totalMinutes = (movieLength - remainingSeconds) / 60; + + const remainingMinutes = totalMinutes % 60; + const totalHours = (totalMinutes - remainingMinutes) / 60; + + const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`; + return result; +} + +console.log(movieLengthFormatter(0)); +console.log(movieLengthFormatter(59)); +console.log(movieLengthFormatter(10000)); +console.log(movieLengthFormatter(-100)); +console.log(movieLengthFormatter(200.4)); // 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 is `console.log` as a function call. // c) Using documentation, explain what the expression movieLength % 60 represents // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators +// This expression is a remainder left after the movieLength value is divided by 60 and represents the value of reimaining seconds. +// % - is a remainder operator, or modulo operator. // d) Interpret line 4, what does the expression assigned to totalMinutes mean? +// From the movieLength variable, we subtract the remainingSeconds value from the movieLength value. +// We then divide the result by 60 to get the totalMinutes value, that is the number of whole minutes in the movie duration. // e) What do you think the variable result represents? Can you think of a better name for this variable? +// The variable result represents the final result of the movie duration in the format of H:M:S. +// The better name for this variable could be movieLengthFormatted. // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer +// There are a couple of edge cases that this code will not work for: +// if movieLength is less than 0, which is not a valid duration, the code will give calculation, but it will not return a valid result. +// if movieLength is a decimal number, the code will give calculation, but the format will not be followed. +// diff --git a/Sprint-1/3-mandatory-interpret/3-to-pounds.js b/Sprint-1/3-mandatory-interpret/3-to-pounds.js index 60c9ace69a..cffdbd3fae 100644 --- a/Sprint-1/3-mandatory-interpret/3-to-pounds.js +++ b/Sprint-1/3-mandatory-interpret/3-to-pounds.js @@ -25,3 +25,8 @@ console.log(`£${pounds}.${pence}`); // To begin, we can start with // 1. const penceString = "399p": initialises a string variable with the value "399p" +// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1): removes the trailing "p" from the string +// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"): pads the string with leading zeros to make it 3 characters long +// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2): extracts the first two characters from the padded string +// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"): extracts the last two characters from the padded string and pads them with leading zeros to make them 2 characters long +// 6. console.log(`£${pounds}.${pence}`);: this line prints the result to the console diff --git a/Sprint-1/4-stretch-explore/chrome.md b/Sprint-1/4-stretch-explore/chrome.md index e7dd5feafe..34058008ca 100644 --- a/Sprint-1/4-stretch-explore/chrome.md +++ b/Sprint-1/4-stretch-explore/chrome.md @@ -12,7 +12,12 @@ invoke the function `alert` with an input string of `"Hello world!"`; What effect does calling the `alert` function have? +- It activates a pop-up window with the text "Hello world!" with "OK" as the button text. The execution is paued until the user clicks the "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? -What is the return value of `prompt`? + +- It activates a pop-up window with the text "What is your name?" with input field and "OK" and "Cancel" buttons. The execution is paused until the user enters a value and clicks the "OK" button. + What is the return value of `prompt`? +- The return value of the prompt function is the value entered by the user in the input field. diff --git a/Sprint-1/4-stretch-explore/objects.md b/Sprint-1/4-stretch-explore/objects.md index 0216dee56a..7896c4db21 100644 --- a/Sprint-1/4-stretch-explore/objects.md +++ b/Sprint-1/4-stretch-explore/objects.md @@ -5,12 +5,47 @@ 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? +function log() +length: 0 +name: "log" +: function () Now enter just `console` in the Console, what output do you get back? - +Console { assert: assert(), clear: clear(), count: count(), countReset: countReset(), debug: debug(), error: overrideMethod(n), info: info(), log: log(), table: table(), trace: overrideMethod(n), … } +assert: function assert() +clear: function clear() +count: function count() +countReset: function countReset() +debug: function debug() +dir: function dir() +dirxml: function dirxml() +error: function overrideMethod(n) +exception: function exception() +group: function group() +groupCollapsed: function groupCollapsed() +groupEnd: function groupEnd() +info: function info() +log: function log() +profile: function profile() +profileEnd: function profileEnd() +table: function table() +time: function time() +timeEnd: function timeEnd() +timeLog: function timeLog() +timeStamp: function timeStamp() +trace: function overrideMethod(n) +warn: function overrideMethod(n) +Symbol(Symbol.toStringTag): "console" +: Object { } Try also entering `typeof console` -Answer the following questions: +- "object" + Answer the following questions: What does `console` store? -What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean? + +- console stores an object that contains a collection of methods (functions) used for debugging and logging information to the browser's console. + What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean? +- `console.log` is a method of the `console` object that logs a message to the console. +- `console.assert` is a method of the `console` object that checks if a condition is true, and if not, throws an error. +- The `.` in `console.log` and `console.assert` is a property access operator. It means that `console` is an object, and `log` and `assert` are its properties or methods.