Understanding JavaScript Errors and How to Handle Them

                                
// This will create and show an error message saying 'Something went wrong'
throw Error('Something went wrong');
// The code below won't run because of the error
console.log('This message won’t be shown');
                              

                                
throw Error('Your password is too weak.'); // This will stop the code and show 'Your password is too weak.'
                              

                                
// Using try...catch to handle errors
try {
  throw Error('This error will be handled');
} catch (e) {
  console.log(e.message); // This will show the error message
}
// Handling a built-in error
const fixedValue = 'Cannot be changed';
try {
  fixedValue = 'New value'; // This will throw a TypeError 
} catch (e) {
  console.log('An error occurred!'); // This message will be shown
}
console.log('Code continues after handling the error');
                              

                                
// Example of catching a ReferenceError in JavaScript
let firstName = "John";
try {
  console.log(firstName + lastName); // lastName is not defined, causing a ReferenceError
} catch (error) {
  console.log('Caught an error:', error.message); // This will show: 'Caught an error: lastName is not defined'
}
                              

                                
let age = 25;
console.log(age + years); // This will cause a ReferenceError because 'years' is not defined.
                              

                                
try {
  eval('function name( { '); // Missing closing parenthesis causes a SyntaxError
} catch (e) {
  console.log('Caught a SyntaxError:', e.message); // This will show: 'Caught a SyntaxError: Unexpected token {'
}
                              

                                
let number = 10;
let text = 'Ten';
try {
  console.log(number + text); // This will cause a TypeError because you can't add a number to a string
} catch (e) {
  console.log('Caught a TypeError:', e.message); // This will show: 'Caught a TypeError: number + text is not a valid operation'
}