Module 1: Technical Preparation - Review of Basics

Introduction to CodeSignal and General Code Assessment (GCA)

Understanding CodeSignal Tasks

Review of Basic Coding Knowledge

In-Depth: JavaScript Fundamentals

Functions: The Building Blocks

Functions are reusable blocks of code that perform specific tasks. They help make your code more organized, readable, and maintainable.

// Function declaration
function greet(name) {
  return `Hello, ${name}!`;
}

// Function expression
const add = function(a, b) {
  return a + b;
};

// Arrow function
const multiply = (a, b) => a * b;

// Using the functions
console.log(greet("Alice"));    // "Hello, Alice!"
console.log(add(5, 3));         // 8
console.log(multiply(4, 2));    // 8

Variables: Storing and Managing Data

Variables allow you to store and manage data in your programs. Understanding variable scope and how to use let, const, and var properly is crucial for writing effective JavaScript.

// Variable declarations
let count = 0;          // Can be reassigned
const PI = 3.14159;     // Cannot be reassigned
var oldWay = true;      // Function-scoped (avoid using var)

// Scope demonstration
function demonstrateScope() {
  let blockScoped = "I'm only visible in this function";
  
  if (true) {
    let innerVariable = "I'm only visible in this block";
    console.log(blockScoped);       // Works fine
    console.log(innerVariable);     // Works fine
  }
  
  // console.log(innerVariable);    // Would cause an error - not defined here
}

// Variable types
let string = "Hello";
let number = 42;
let boolean = true;
let array = [1, 2, 3];
let object = { name: "JavaScript", purpose: "Programming" };

Problem-Solving Strategy

When approaching a new problem, follow these steps:

1. Understand the problem: Read the problem statement carefully and identify the inputs, expected outputs, and constraints.
2. Break it down: Divide the problem into smaller, manageable parts.
3. Plan your solution: Think about the algorithm or approach before writing any code.
4. Code your solution: Implement your planned approach.
5. Test and debug: Check your solution with various test cases, including edge cases.
6. Refactor: Look for ways to improve your solution's clarity, efficiency, or readability.

Common Mistakes to Avoid

• Not initializing variables before using them
• Confusing assignment (=) with comparison (== or ===)
• Forgetting to return values from functions
• Misunderstanding variable scope
• Using the wrong operator for the intended operation