London | 26-ITP-Sept | Fung Nin Lee | Sprint 2 | JavaScript Fundamentals

Sprint-2/1-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
+
+= mean assignment operator. Computer will calculate the result of "count + 1" and update the variable with the result.
+In this question, variable "count" changed from 0 to 1.

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

@@ -5,6 +5,7 @@ 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
+  console.log(initials)

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

@@ -11,13 +11,15 @@
 
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
-const base = filePath.slice(lastSlashIndex + 1);
+const base = filePath.slice(lastSlashIndex);
 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.slice(base.lastIndexOf(".") + 1);
+
+console.log(ext)
 
 // https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,10 @@ 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)
+
+math.floor is round down the number returns to largest integer less than or equal to a given number.
+math.random() could generate the number from 0 to <1 b random.
+maximum refer to 100 and minimum refer to 0.
+The calculation of num is different everytime because of math.random()

Sprint-2/2-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?
+We don't want the computer to run these 2 lines - how can we solve this problem?
+
+adding // before the lines. 

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

@@ -2,3 +2,8 @@
 
 const age = 33;
 age = age + 1;
+
+console.log(age)
+
+The error is "Assignment to constant variable." Constant value could not be alternated. 
+if line 3 const changed to let the code could be executed.

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

@@ -3,3 +3,5 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+Initialization should access before the declaration. 

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

@@ -7,3 +7,5 @@ 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 is for text or array only. Need to change card number from number to text. Add ''for 4533787178994213. 

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

@@ -1,2 +1,4 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+
+//integer/number could not start for the initiation.

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;
@@ -12,11 +12,21 @@ 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
+//A: 3
+//carPrice = Number(carPrice.replaceAll(",", ""));
+//priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+//console.log(`The percentage change is ${percentageChange}`);
 
 // 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?
+//A: line 5. there should add , between "," and "" to divided 2 conditions.
 
 // c) Identify all the lines that are variable reassignment statements
+//A: carPrice = Number(carPrice.replaceAll(",", ""));
+//priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // d) Identify all the lines that are variable declarations
+//const priceDifference = carPrice - priceAfterOneYear;
+//const percentageChange = (priceDifference / carPrice) * 100;
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+//A: replacing , with empty string.

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

@@ -12,14 +12,22 @@ 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?
+// A: 6
 
 // b) How many function calls are there?
+//A: 1
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// % operate the remainder of 2 numbers divided. In this case, remainingSecond is the remainder of  8784 second (movieLength)
+// divided 60. And the remainingSecond is 24.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+//A: totalMinutes get the result form movieLength (8784) minus remainingSecond (24). The result is 8760. 
+//The totalMinutes is 8760 divide 60 = 146.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+//A: Duration
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Yes. Because the variables declaration stated clearly.

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

@@ -25,3 +25,11 @@ 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 = "399": returning with shorten less index to erase p
+// 3. const paddedPenceNumberString = "399"; It pads the string with the given length with specific string. 
+// In this case, penceStringWithoutTrailingP (399) is already with 3 digis, so no change.
+// 4. const pounds = "3", getting part of the string by subString and target to get the string without last 2 digis.
+// 5. const pence = "99", subString indexStart counted by length of paddedPenceNumberString - 2 that is 1. So the result of 
+//subString is 99. padEnd result the string with given length from the end of String. "99" length is 2 and already match
+//with the function. no change.
+//6. console.log = £3.99. The number refer to pounds and pence.

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

@@ -8,8 +8,11 @@ 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?
+A: The dialogue box come out with an optional message.
 
 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`?
+A: There have a dialogue box appear and able to submit information. 
+After submit the information (Name). The information submitted to server.

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?
+A: ƒ log() { [native code] }
 
 Now enter just `console` in the Console, what output do you get back?
+A: console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
 Try also entering `typeof console`
+A: 'object'
 
 Answer the following questions:
 
 What does `console` store?
+A： console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
+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: 12700000, 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
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+A：log and assert are the functions under object "console". '.' mean calling for function.

Sprint-2/prep/PasswordChecker.js

@@ -0,0 +1,14 @@
+const password = "secretword123";
+const userInput = "thisiswrong";
+const adminPassword = "override";
+let response = "";
+
+if (userInput === password){ 
+  response = "Correct password entered";
+} else if (userInput === adminPassword){
+  response = "Admin access granted";
+} else {
+  response = "Incorrect password!";
+}
+
+console.log(response);

Sprint-2/prep/comparison.js

@@ -0,0 +1 @@
+console.log(42 === 42);

Sprint-2/prep/errors.js

@@ -0,0 +1,14 @@
+const password = "secretword123";
+const userInput = "thisiswrong";
+const adminPassword = "override";
+const response = "";
+
+if (userInput === password){ 
+  response = "Correct password entered";
+} else if (userInput === adminPassword){
+  response = "Admin access granted";
+} else {
+  response = "Incorrect password!";
+}
+
+console.log(response);

Sprint-2/prep/fact.js

@@ -0,0 +1 @@
+console.log("I am from Hong Kong.");

Sprint-2/prep/greeting.js

@@ -0,0 +1,5 @@
+
+const name="Roger!";
+let greeting = "hello!";
+greeting = "Goodbye!"
+console.log(`${greeting}, ${name}`);

Sprint-2/prep/hello_world.js

@@ -0,0 +1 @@
+console.log("oh my god1")