catalyst 1.1.1

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Catalyst is a dependency injection container for the dart language. It's fast, reliable and easy to understand.

📦 Installation

Add the following to your pubspec.yaml:

  catalyst: ^1.1.0

Then run pub get

💡 Usage


import 'package:catalyst/catalyst.dart';

Register Services

To register a service you have to call the register-method.

Container.register(String id, dynamic service, [List<dynamic> arguments])
idThe unique id of the serviceapp.my_service
serviceThe service target(int a) => a * 2
argumentsThe arguments for the service. Entries with @-prefix are service references[1, 'foo', bar]

Register a service with static arguments

Since not all services need an service injection, the arguments array also supports static entries.

Container container = new Container();

container.register('app.my_service', (String name) {
  return 'Hello $name';
}, ['Your Name']);

var knownServices = container.registeredServices; // Contains the registered Service 

Register a service with a service dependency

In most cases you need another registered service in your service. In that case you can pass the service name with a @-prefix to reference to it. The (sub-) dependencies are solved recursively.

Container container = new Container();

container.register('app.another_service', () {
  return {'name': 'Jane', 'age': '24'};

container.register('app.my_service', (dynamic anotherService) {
return "Name: ${anotherService['name']}, Age: ${anotherService['age']}";
}, ['@app.another_service']);

print(container.get('app.my_service')); // Outputs "Name: Jane, Age: 24"

Register a class as a service

You can also register a class as a service. If the service is loaded, the constructor gets called with the dependencies.

main() {
  Container container = new Container();

  // Register the first service
  container.register('namer', () => 'John Doe');

  // Register the second service. The constructor will be called with the passed arguments
  container.register('greeter', Greeter, ['@namer']);

  // Retrieve the greeter
  var greeter = container.get('greeter');

  // Greet
  print(greeter.greet()); // Outputs "Hello, my Name is John Doe!"

class Greeter {
  String name;

  Greeter( {}

  String greet() {
    return "Hello, my Name is $name!";

Load a service

To load a service you have to call the get-method.
Once a service is loaded, it remains in memory at runtime. When the same service is loaded again, the first instance is returned.

Container.get(String id)
idThe unique id of the
Container container = new Container();

// Register the first service
container.register('namer', () => 'Catalyst');

container.get('namer'); // returns "Catalyst"

Add Parameters

The service container also supports static parameters.
You can add a parameter using the addParameter-method

Container.addParameter(String name, dynamic value)
nameThe unique name of the
valueThe parameter valuelocalhost

To pass a parameter to a service, add before and after the name a '%': %name.of.the.parameter%

Container container = new Container();
container.addParameter('', 'localhost');

container.register('db.context', (String hostname) {
return 'Connecting to $hostname';
}, ['']);

print(container.get('db.context')); // Outputs "Connecting to localhost"

🔌 Service auto wiring

Catalyst supports auto wiring of services. That means, that you only need to register the service without passing depending service names as arguments. (Strong typing is required).

For example:

main() {
  Container container = new Container();
  container.register('greeter', SimpleGreeter);
  container.register('greeting_printer', (SimpleGreeter greeter) {

  container.get('greeting_printer'); // Outputs "Hello from Catalyst!"

class SimpleGreeter {

  String greet(String name) {
    return "Hello from $name!";

You can disable this behaviour with setting Container.autoWire = false;

🔬 Testing

$ pub run test

🤝 Contribute

Feel free to fork and add pull-requests 🤓


Tests fixed

  • Using Exception.toString() instead of accessing the message property


Code refactored

  • Container.get() method splitted into multiple methods
    • _loadAndRetrieveService() loads the service and stores it in the _loadedServices property
    • _injectServicesAndParameters() fetches the @foobar services and %foo_bar% parameters and inject them
    • _doAutoWire() auto wires the injections
  • Service.getMetadata() and Service.targetMirror added


  • First Release
  • Example code in /example added


  • Auto wiring implemented (See "Service auto wiring" in the README)


  • Initial release


 * This file is part of the Catalyst package.
 * Copyright 2018 by Julian Finkler <>
 * For the full copyright and license information, please read the LICENSE
 * file that was distributed with this source code.

import 'package:catalyst/catalyst.dart';

main() {
  Container container = new Container();

  // Register the StackAsAService in the container
  container.register('shared_stack', StackAsAService);

  // Get the registered service from the container
  StackAsAService stack = container.get('shared_stack');

  // Modify the stack
  print(stack.length); // Outputs 0


  print(stack.length); // Outputs 2

  print(stack.entries); // Outputs [Hello, World]

  // Retrieve the  same service again from the container
  StackAsAService anotherStack = container.get('shared_stack');

  print(anotherStack.length); // Outputs 2

  print(anotherStack.entries); // Outputs [Hello, World]

  // Modify it...

  // And the first variable is also modified
  print(stack.length); // Outputs 2

  print(stack.entries); // Outputs [Hello]

class StackAsAService {
  List<String> _entries = new List<String>();

  void add(String entry) {

  void remove(String entry) {
    _entries.removeWhere((e) => e == entry);

  List<String> get entries => _entries;

  int get length => _entries.length;

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:

  catalyst: ^1.1.1

2. Install it

You can install packages from the command line:

with pub:

$ pub get

Alternatively, your editor might support pub get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:catalyst/catalyst.dart';
Version Uploaded Documentation Archive
1.1.1 Jul 15, 2018 Go to the documentation of catalyst 1.1.1 Download catalyst 1.1.1 archive
1.1.0 Apr 24, 2018 Go to the documentation of catalyst 1.1.0 Download catalyst 1.1.0 archive
1.0.0 Apr 23, 2018 Go to the documentation of catalyst 1.0.0 Download catalyst 1.0.0 archive
0.0.2 Apr 15, 2018 Go to the documentation of catalyst 0.0.2 Download catalyst 0.0.2 archive
0.0.1 Apr 14, 2018 Go to the documentation of catalyst 0.0.1 Download catalyst 0.0.1 archive
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The package version is not analyzed, because it does not support Dart 2. Until this is resolved, the package will receive a health and maintenance score of 0.

Issues and suggestions

Support Dart 2 in pubspec.yaml.

The SDK constraint in pubspec.yaml doesn't allow the Dart 2.0.0 release. For information about upgrading it to be Dart 2 compatible, please see


Package Constraint Resolved Available
Direct dependencies
Dart SDK >=1.24.3 <2.0.0