dependency_initializer

Description:

dependency initializer

Dependency initializer #
Initializer utility of dependencies for Dart & Flutter projects.
The utility does not depend on Flutter SDK to be able to use it for Dart projects as well.
Usage #

Prepare list of initialize steps:

final List<InitializationStep<Process>> coreStepList = [
InitializationStep(
title: "Config",
initialize: (
Process process,
) =>
process.config = Config$(),
),
];
final List<InitializationStep<Process>> dataStepList = [
InitializationStep(
title: "HttpClient",
initialize: (
Process process,
) =>
process.client = HttpClient$(
config: process.config!,
),
),
InitializationStep(
title: "Api",
initialize: (
Process process,
) =>
process.api = Api$(
client: process.client!,
),
),
InitializationStep(
title: "Dao",
initialize: (
Process process,
) =>
process.dao = Dao$(
config: process.config!,
),
),
InitializationStep(
title: "Storage",
initialize: (
Process process,
) =>
process.storage = Storage$(
config: process.config!,
),
),
InitializationStep(
title: "Repository",
initialize: (
Process process,
) =>
process.repository = Repository$(
api: process.api!,
dao: process.dao!,
storage: process.storage!,
),
),
];
final List<InitializationStep<Process>> blocStepList = [
InitializationStep(
title: "Bloc",
initialize: (
Process process,
) =>
process.bloc = Bloc(
repository: process.repository!,
),
),
];
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Create initializer and start initialize process:

final Initializer initializer = Initializer<Process, Result>(
creteProcess: () => Process(),
stepList: [
...coreStepList,
...dataStepList,
...blocStepList,
],
onSuccess: (
Result result,
Duration duration,
) {
// Success result of initialization
},
);
await initializer.run();
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Use cases #
Initializer has several use cases:

Direct.
For example, if you want the Flutter application to show a native splash screen when it starts, and then launch the first widget.

final Initializer initializer = Initializer<Process, Result>(
creteProcess: () => Process(),
stepList: stepList,
onSuccess: (
DependencyInitializationResult<Process, Result> initializationResult,
Duration duration,
) => runApp(
ApplicationWidget(
result: initializationResult.result,
),
),
onError: (
Object? error,
StackTrace stackTrace,
Process process,
DependencyInitializationStep<Process> step,
Duration duration,
) => runApp(
const ApplicationErrorWidget(),
),
);
await initializer.run();
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With async completer.
For example, you have a widget that displays its splash screen, and this widget must be rebuilt asynchronously using the initialization compiler.

final Initializer initializer = Initializer<Process, Result>(
creteProcess: () => Process(),
stepList: stepList,
onStart: (
Completer<DependencyInitializationResult<Process, Result>> completer,
) => runApp(
ApplicationWidget(
completer: completer,
),
),
onError: (
Object? error,
StackTrace stackTrace,
Process process,
DependencyInitializationStep<Process> step,
Duration duration,
) => runApp(
const ApplicationErrorWidget(),
),
);
await initializer.run();
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Reinitialization from result.
For example, in the runtime of a Flutter application, you need to reinitialize your new dependencies for the new environment and return the first widget of the Flutter application again.

await initializationResult.reRun(
stepList: [
InitializationStep(
title: "Config",
initialize: (
Process process,
) =>
process.config = AnotherConfig(),
),
...initializationResult.reinitializationStepList,
],
onSuccess: (
DependencyInitializationResult<Process, Result> initializationResult,
Duration duration,
) => runApp(
ApplicationWidget(
result: initializationResult.result,
),
),
onError: (
Object? error,
StackTrace stackTrace,
Process process,
DependencyInitializationStep<Process> step,
Duration duration,
) => runApp(
const ApplicationErrorWidget(),
),
);
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Additional information #
For more details see example project.
And feel free to open an issue if you find any bugs or errors or suggestions.