RequestStatus<ResultType> class sealed

When one is dealing with ui responses to different request states, in the course of it, usually there are four states of interest Idle, Loading, Succeded or Failed.

So the convenience generic union type

RequestStatus<ResultType>

serves the purpose of modeling those states. Idle and Loading, carry no inner state, but

Succeeded<ResultType>().data = ResultType data;

contains a field data of type ResultType. And the

Failed().error = AppError error;

contains a field error of type AppError. Where AppError is the convenience type that models errors in the app.

To deal with the request states one should use one of the unions methods. The .map forces you to deal with all the four states explicitly, passing callbacks for each state with undestructured states.

Example:


  Widget build(context) {

    final someRequestStatus = someStateManagement.desiredRequestStatus;

    return someRequestStatus.map(
              idle: (idle) => "widget for idle state",
              loading: (loading) => "widget for loading state",
              succeeded: (succeeded) => "widget for succeeded state using possibly data within succeeded.data",
              failed: (failed) => "widget for failed state using possibly AppError within failed.error",
          );

  }

The .when forces you to deal with all the four states explicitly, passing callbacks for each state with destructured states. /// Example:


  Widget build(context) {

    final someRequestStatus = someStateManagement.desiredRequestStatus;

    return someRequestStatus.when(
              idle: () => "widget for idle state",
              loading: () => "widget for loading state",
              succeeded: (data) => "widget for succeeded state using possibly data within data",
              failed: (error) => "widget for failed state using possibly AppError within error",
          );

  }

and one also might want to not deal explicitly with all states diferently, so there are the .maybeMap, and .maybeWhen methods where you need only expclitly to pass a orElse callback.

Example:


  Widget build(context) {

    final someRequestStatus = someStateManagement.desiredRequestStatus;

    return someRequestStatus.maybeWhen(
              orElse: () => "default widget to be displayed other wise the current state is not specified in other callbacks"
              loading: () => "widget for loading state",
              succeeded: (data) => "widget for succeeded state using possibly data within succeeded.data",
          );

  }

So, RequestStatus provides a safe and declarative way to always deal with all possible states of a request.

Annotations
  • @freezed

Constructors

RequestStatus.failed(AppError error)
Type representing the Failed state of a request when it is not successful, bringing possibly the modeled error
const
factory
RequestStatus.fromResult(Result<ResultType> result)
Factory for helping building a RequestStatus from a Result input. It produces a Failed status if the input is a Failure, and a Succeeded otherwise
factory
RequestStatus.idle()
Type representing the Idle state of a request still not fired
const
factory
RequestStatus.loading()
Type representing the Loading state of a request when it is waiting for a response
const
factory
RequestStatus.succeeded(ResultType data)
Type representing the Succeeded state of a request when it is successful, bringing possibly the modeled response data
const
factory

Properties

asFailed → Failed
Cast this into a Failed, and throw an exception if the cast fails! It might be tempting to just cast the RequestStatus into the desired type, but it's strongly advised to not do that indiscriminately. Although, it might be convenient to have this cast sometimes. Use it wisely!
no setter
asIdle → Idle
Cast this into an Idle, and throw an exception if the cast fails! It might be tempting to just cast the RequestStatus into the desired type, but it's strongly advised to not do that indiscriminately. Although, it might be convenient to have this cast sometimes. Use it wisely!
no setter
asLoading → Loading
Cast this into a Loading, and throw an exception if the cast fails! It might be tempting to just cast the RequestStatus into the desired type, but it's strongly advised to not do that indiscriminately. Although, it might be convenient to have this cast sometimes. Use it wisely!
no setter
asSucceeded → Succeeded
Cast this into a Succeeded, and throw an exception if the cast fails! It might be tempting to just cast the RequestStatus into the desired type, but it's strongly advised to not do that indiscriminately. Although, it might be convenient to have this cast sometimes. Use it wisely!
no setter
hashCode → int
The hash code for this object.
no setterinherited
isFailed → bool
no setter
isIdle → bool
no setter
isLoading → bool
no setter
isSucceeded → bool
no setter
maybeData → Maybe<ResultType>
Getter that results in a Maybe that is Just if the RequestStatus is Succeeded and Nothing otherwise
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited