module-4.1-types-of-errors.md

4.1. Types of Errors

In web development, errors can occur at different stages of the development and execution of your code. Understanding the types of errors is crucial for effective error handling and debugging.

Syntax Errors

Syntax errors, often referred to as "parsing errors," occur when your code violates the syntax rules of the programming language. These errors prevent your code from being executed.

Example:

// Syntax error due to missing closing parenthesis
function add(a, b {
  return a + b;
}

In this example, the missing closing parenthesis in the function parameter list results in a syntax error.

Runtime Errors

Runtime errors occur during the execution of your code. They can be caused by various issues, such as referencing an undefined variable or attempting an operation that's not supported.

Example:

// Runtime error due to dividing by zero
function divide(a, b) {
  if (b === 0) {
    throw new Error('Division by zero is not allowed.');
  }
  return a / b;
}

console.log(divide(10, 0)); // Throws a runtime error

In this example, we throw a runtime error when attempting to divide by zero to prevent an undesirable outcome.

Logical Errors

Logical errors are more subtle and challenging to detect. They occur when your code doesn't produce the expected or desired results, even though it runs without syntax or runtime errors.

Example:

// Logical error in calculating the sum of an array
function calculateSum(arr) {
  let sum = 0;
  for (let i = 0; i < arr.length; i++) {
    sum += arr[i];
  }
  return sum;
}

const numbers = [1, 2, 3, 4, 5];
console.log(calculateSum(numbers)); // Incorrect result (logical error)

In this example, a logical error in the calculateSum function leads to an incorrect result, as it doesn't properly calculate the sum of the array elements.

Benefits

• Understanding the types of errors helps you identify and address issues in your code effectively.
• Properly categorizing and diagnosing errors is crucial for implementing appropriate error handling strategies.

Recognizing and differentiating between syntax errors, runtime errors, and logical errors is essential for efficient debugging and error handling in web development.