52 lines
1.2 KiB
Dart
52 lines
1.2 KiB
Dart
// Template asset: copy or adapt this only when the project does not already
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// have an equivalent typed result/error model.
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/// Utility class to wrap result data
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///
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/// Evaluate the result using a switch statement:
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/// ```dart
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/// switch (result) {
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/// case Ok():
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/// print(result.value);
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/// case Error():
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/// print(result.error);
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/// }
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/// ```
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sealed class Result<T> {
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const Result();
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/// Creates an instance of Result containing a value
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factory Result.ok(T value) => Ok(value);
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/// Create an instance of Result containing an error
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factory Result.error(Exception error) => Error(error);
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/// Convenience method to cast to Ok
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Ok<T> get asOk => this as Ok<T>;
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/// Convenience method to cast to Error
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Error<T> get asError => this as Error<T>;
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}
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/// Subclass of Result for values
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final class Ok<T> extends Result<T> {
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const Ok(this.value);
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/// Returned value in result
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final T value;
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@override
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String toString() => 'Result<$T>.ok($value)';
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}
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/// Subclass of Result for errors
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final class Error<T> extends Result<T> {
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const Error(this.error);
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/// Returned error in result
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final Exception error;
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@override
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String toString() => 'Result<$T>.error($error)';
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}
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