class ValidationError extends Error {
constructor(message) {
super(message);
this.name = "ValidationError";
}
}
let json = '{"age": 20}';
try {
let user = JSON.parse(json);
if(!user.name) {
throw new ValidationError("'name' is required.");
}
if(!user.age) {
throw new ValidationError("'age' is required.");
}
console.log(user.name);
console.log(user.age);
} catch (error) {
if(error instanceof SyntaxError) {
console.log(`JSON Error: ${error.message}`);
} else if(error instanceof ValidationError) {
console.log(`Invalid data: ${error.message}`);
} else if(error instanceof ReferenceError) {
console.log(error.message);
} else {
console.log(error.stack);
}
}
