Error Handling In Flutter: Using Try/catch And The Result Type

Aspect	try/catch	Result Type
Usage	Used to catch and handle exceptions	Used to represent success or error conditions
Syntax	try { … } catch (e) { … }	Result.success(value) or Result.error(e)
Handling Exceptions	Catch and handle specific types of exceptions	Handle success and error cases explicitly
Error Information	Provides access to the caught exception	Returns error message or value
Error Propagation	Exceptions can propagate up the call stack	Explicitly handle errors using when
Error Type Safety	Requires handling all possible exceptions	Forces explicit handling of success and error
Code Organization	Requires placing relevant code in try block	Separates success and erro

Exception Handling with try/catch

try {
  // Code that may throw an exception
  int result = 10 ~/ 0; // Division by zero
  print('Result: $result');
} catch (e) {
  // Exception handling
  print('Error: $e');
}

Using Result type for error handling

import 'package:dartz/dartz.dart';

Either<String, int> divideNumbers(int a, int b) {
  try {
    if (b == 0) {
      return Left('Error: Division by zero');
    }
    int result = a ~/ b;
    return Right(result);
  } catch (e) {
    return Left('Error: $e');
  }
}

void main() {
  Either<String, int> result = divideNumbers(10, 0);
  result.fold(
    (error) => print(error),
    (value) => print('Result: $value'),
  );
}

In the first example, a try/catch block is used to handle the exception that may occur during division by zero. The catch block catches the exception and prints the error message.

In the second example, the Either type from the dartz package is used to represent the result as either a left value (error) or a right value (success). The divideNumbers function returns an Either type indicating either the result of the division or an error message. The fold method is used to handle the result by providing separate functions for the left (error) and right (success) cases.

These examples demonstrate different approaches to handle exceptions and errors in Flutter using try/catch and the Result type.