So I've got a pure Polymer app. Currently, in some elements I have methods that call to my Firebase database, and handle related processing and whatnot, which I then <template repeat=...> into my element. This doesn't seem right, as it's encouraged that Polymer elements are reusable. I also do things like dependency injection e.g. <my-element app="{{app}}"> so I have access to global settings and such.
What I end up with is a structure like:
index.dart -> <my-app-as-an-element app=... -> <child-elements app=...
Is there a better way to architect things? Like, should the business logic happen in lib/src/some_controller.dart which is imported into index.dart and has the business logic methods? How would I pass that through to the child elements that need access to those methods? Basically, some best practices and approaches would be helpful.
I use Model classes which are structured in a way that reflects the GUI structure and I bind them to the Polymer elements like shown below. Similar with the controllers but this would get out of proportion for an SO answer.
I didn't test this code - this is just to demonstrate the idea.
import 'package:polymer/polymer.dart';
class AppModel {
var loginModel = new LoginModel();
var moviesModel = new MoviesModel();
var actorsModel = new ActorsModel();
}
class LoginModel extends Observable {
@observable bool isAuthenticated;
@observable String userName;
@observable String email;
}
class MoviesModel {
final List<MovieModel> movies = toObservable(<MovieModel>[]);
}
class MovieModel extends Observable {
@observable String id;
@observable String name;
@observable int rating;
final List<ActorModel> actors = toObservable(<ActorModel>[]);
}
class ActorsModel {
final List<ActorModel> actors = toObservable(<ActorModel>[]);
}
class ActorModel extends Observable {
@observable String id;
@observable String firstName;
@observable String middleName;
@observable String lastName;
@observable DateTime birthDate;
final List<MovieModel> movies = toObservable(<MovieModel>[]);
}
.
<polymer-element name="login-dropdown">
<template>
<template if="model.isAuthenticated">
<label for="userName"><input id="userName" value="{{model.userName}}" disabled></label>
<label for="email"><input id="email" value="{{model.email}}" disabled></label>
<button on-click="{{handleSignOut}}">Sign out</button>
</template>
<template if="!model.isAuthenticated">
<label for="userName"><input id="userName" value="{{model.userName}}"></label>
<button on-click="{{handleSignIn}}">Sign out</button>
</template>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('login-dropdown')
class LoginDropdown extends PolymerElement {
LoginDropdown.created() : super.created();
@PublishedProperty(reflect: true) MoviesModel model;
}
</script>
</polymer-element>
<polymer-element name="app-element">
<template>
<header-toolbar>
<login-dropdown-button>
<login-dropdown model="{{model.loginModel}}"></login-dropdown>
</login-dropdown-button>
</header-toolbar>
<tab-control>
<tab-panel label="Movies">
<movies-panel model="{{model.moviesModel}}"></movies-panel>
</tab-panel>
<tab-panel label="Actors">
<actors-panel model="{{model.actorsModel}}"></actors-panel>
</tab-panel>
</tab-control>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('app-element')
class AppElement extends PolymerElement {
AppElement.created() : super.created();
AppModel model = new AppModel();
}
</script>
</polymer-element>
<polymer-element name="movies-panel">
<template>
<template repeat="{{movie in model.movies}}">
<movie-panel model="{{movie}}"></movie-panel>
</template>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('movies-panel')
class MoviesPanel extends PolymerElement {
MoviesPanel.created() : super.created();
@PublishedProperty(reflect: true) MoviesModel model;
}
</script>
</polymer-element>
<polymer-element name="movie-panel">
<template>
<div data-id="{{model.id}}">
<div><span>Name:</span><span>{{model.name}}</span></div>
<div><span>Rating:</span><span>{{model.rating}}</span></div>
</div>
<template repeat="{{actor in model.actors}}">
<actor-panel model="{{actor}}"></actor-panel>
</template>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('movies-panel')
class MoviesPanel extends PolymerElement {
MoviesPanel.created() : super.created();
@PublishedProperty(reflect: true) MoviesModel model;
}
</script>
</polymer-element>
<polymer-element name="actors-panel">
<template>
<template repeat="{{actor in model.actors}}">
<actor-panel model="{{actor}}"></actor-panel>
</template>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('actors-panel')
class ActorsPanel extends PolymerElement {
ActorsPanel.created() : super.created();
@PublishedProperty(reflect: true) ActorsModel model;
}
</script>
</polymer-element>
<polymer-element name="actor-panel">
<template>
<div data-id="{{model.id}}">
<div><span>First name:</span><span>{{model.firstName}}</span></div>
<div><span>Middle name:</span><span>{{model.middleName}}</span></div>
<div><span>Last name:</span><span>{{model.lastName}}</span></div>
<div><span>Date of birth:</span><span>{{model.birthDate}}</span></div>
</div>
<template repeat="{{movie in model.movies}}">
<movie-panel model="{{movie}}"></movie-panel>
</template>
</template>
<script type="application/dart">
import 'package:polymer/polymer.dart';
import 'model.dart';
@CustomTag('actor-panel')
class ActorPanel extends PolymerElement {
ActorPanel.created() : super.created();
@PublishedProperty(reflect: true) ActorModel model;
}
</script>
</polymer-element>
See also Use a class as attribute for a dart polymer element for more interesting options.