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JavaScript Basics Coding Challenge - Answer Key

This answer key provides solutions for each task in the JavaScript Basics Coding Challenge. Your answers might not be exactly the same, as the specific values or data you use may vary. The primary goal is to ensure you understand the fundamental concepts and can apply them correctly.

Important Note:

When reviewing your peers' submissions, please use the provided rubric to assess each task thoroughly. Ensure that your feedback is constructive and based on the criteria outlined in the rubric.

Task 1: Variables and Data Types

Scenario: Employee Information

You are working in a company's HR department and need to store and manage basic employee information.

Requirements:

  • Declare a variable employeeName using let and assign it the employee's name as a string.
  • Declare a variable employeeID using const and assign it the employee's ID as a number.
  • Declare a variable isActive using var and assign it a boolean value true to indicate the employee is currently active.
  • Log each variable's value and its type to the console.

Answer:

// Task 1: Variables and Data Types
let employeeName = "Alice Johnson";
const employeeID = 12345;
var isActive = true;

console.log(employeeName); // Output: "Alice Johnson"
console.log(typeof employeeName); // Output: "string"

console.log(employeeID); // Output: 12345
console.log(typeof employeeID); // Output: "number"

console.log(isActive); // Output: true
console.log(typeof isActive); // Output: "boolean"

Explanation:

  • let is used to declare a variable that can be reassigned, suitable for employeeName since names can potentially change.
  • const is used for employeeID since an ID should be constant and not change once assigned.
  • var is used for isActive, although it's generally advisable to use let or const in modern JavaScript for better scope management. Here, it illustrates an older style.
  • typeof is a JavaScript operator that returns the data type of the variable.

Task 2: Compound Data Types

Scenario: Product Inventory Management

You are responsible for managing a list of products in a store's inventory.

Requirements:

  • Declare an array products using let and initialize it with at least three product names.
  • Declare an object productDetails using const with properties name, price, and inStock.
  • Log the array and the object to the console.

Answer:

// Task 2: Compound Data Types
let products = ["Laptop", "Smartphone", "Tablet"];
const productDetails = {
  name: "Laptop",
  price: 1200,
  inStock: true
};

console.log(products); // Output: ["Laptop", "Smartphone", "Tablet"]
console.log(productDetails); // Output: { name: "Laptop", price: 1200, inStock: true }

Explanation:

  • Arrays are used to store multiple items of the same type. Here, products holds a list of product names.
  • Objects are used to store related data and functions together. productDetails contains properties describing a product.
  • Logging these to the console helps visualize the data structure and its contents.

Task 3: Assignment Operators

Scenario: Financial Calculations

You are working in the finance department and need to perform various calculations on an account balance.

Requirements:

  • Declare a variable accountBalance using let and initialize it with a number representing the initial balance.
  • Use +=, -=, *=, /=, and %= to update the value of accountBalance for different transactions.
  • Log the updated value of accountBalance after each operation.

Answer:

// Task 3: Assignment Operators
let accountBalance = 1000;

accountBalance += 200; // Deposit
console.log(accountBalance); // Output: 1200

accountBalance -= 150; // Withdrawal
console.log(accountBalance); // Output: 1050

accountBalance *= 1.05; // Interest
console.log(accountBalance); // Output: 1102.5

accountBalance /= 2; // Halving due to split
console.log(accountBalance); // Output: 551.25

accountBalance %= 100; // Modulo operation
console.log(accountBalance); // Output: 51.25

Explanation:

  • Assignment operators (+=, -=, *=, /=, %=) are used to perform arithmetic operations and update the value of a variable in a single step.
  • Each operation modifies accountBalance to reflect transactions like deposits, withdrawals, interest calculations, etc.
  • The use of assignment operators simplifies the syntax and makes the code more readable.

Task 4: Comparison Operators

Scenario: Employee Performance Evaluation

You are evaluating employees based on their performance scores.

Requirements:

  • Declare variables employeeScore1 and employeeScore2 with numerical values representing two employees' scores.
  • Compare employeeScore1 and employeeScore2 using >, <, >=, <=, ===, and !==.
  • Log the results of each comparison to the console.

Answer:

// Task 4: Comparison Operators
let employeeScore1 = 85;
let employeeScore2 = 90;

console.log(employeeScore1 > employeeScore2); // Output: false
console.log(employeeScore1 < employeeScore2); // Output: true
console.log(employeeScore1 >= 85); // Output: true
console.log(employeeScore2 <= 90); // Output: true
console.log(employeeScore1 === 85); // Output: true
console.log(employeeScore1 !== employeeScore2); // Output: true

Explanation:

  • Comparison operators (>, <, >=, <=, ===, !==) are used to compare two values.
  • These comparisons return boolean values (true or false) based on the relation between employeeScore1 and employeeScore2.
  • This is useful in scenarios where decisions are made based on comparisons, like performance evaluations.

Task 5: Logical Operators

Scenario: Access Control System

You are developing an access control system to determine if a user has access to certain sections of a building.

Requirements:

  • Declare variables hasKeyCard and hasPermission with boolean values.
  • Combine these variables using && and || to determine if the user can access different areas.
  • Use the ! operator to reverse a boolean value and log the results.

Answer:

// Task 5: Logical Operators
let hasKeyCard = true;
let hasPermission = false;

console.log(hasKeyCard && hasPermission); // Output: false
console.log(hasKeyCard || hasPermission); // Output: true
console.log(!hasKeyCard); // Output: false

Explanation:

  • Logical operators (&&, ||, !) are used to combine or negate boolean expressions.
  • && (AND) returns true only if both operands are true.
  • || (OR) returns true if at least one operand is true.
  • ! (NOT) reverses the boolean value.
  • This logic is fundamental in control flow and decision-making processes, such as access control systems.

Note: When conducting peer reviews, make sure to use the rubric provided to evaluate each submission based on correctness, code clarity, and adherence to JavaScript best practices. Your constructive feedback will help your peers improve their coding skills!