ember-contextual-services
v0.2.0
Published
Services for object instances
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ember-contextual-services
Services, for instances.
Installation
ember install ember-contextual-services
Usage
First define an instance service for an object type, eg for an ember-data Person
:
// app/contextual-services/person.js
import ContextualService from 'ember-contextual-services';
import computed from 'ember-computed';
export default ContextualService.extend({
fullName: computed('model.firstName', 'model.lastName', function() {
return [this.get('model.firstName'), this.get('model.lastName')].join(' ');
})
});
Then we can inject the contextual-service
service and fetch the instance service for an object using serviceFor
:
// app/components/x-person/component.js
import Component from 'ember-component';
import service from 'ember-service/inject';
export default Component.extend({
contextualService: service(),
person: null,
doSomething() {
const personService = this.get('contextualService').serviceFor(this.get('person'));
personService.get('fullName');
}
});
As a shorthand, instead of injecting and looking up using the contextual-service
we can use serviceFor
which is syntactical sugar for the same:
// app/components/x-person/component.js
import Component from 'ember-component';
import { serviceFor } from 'ember-contextual-services';
export default Component.extend({
personService: serviceFor('person'),
person: null,
doSomething() {
return this.get('personService').get('fullName');
}
});
Or in templates we can use the contextual-service
helper:
{{get (contextual-service person) 'fullName'}}
For simple properties, this is a bit overkill, but where it comes into its own is in conjunction with ember-concurrency:
// app/contextual-services/person.js
import ContextualService from 'ember-contextual-services';
import { task, timeout } from 'ember-concurrency';
export default ContextualService.extend({
debouncedSave: task(function * () {
yield timeout(1000)
yield this.get('model').save();
}).restartable();
});
Contexts
serviceFor
takes a 2nd parameter as a "context" so you can split out functionality for an object type across separate files.
For example serviceFor(person, 'display')
will lookup the service from app/contextual-services/person/display.js
instead of just app/contextual-services/person.js
.
Service lookup
By default serviceFor
will use the ember-data modelName
in order to find the service.
You can change this by extending the service and overriding contextualServiceScope
:
import ContextualServicesService from 'ember-contextual-services/services/contextual-service';
export default ContextualServicesService.extend({
contextualServiceScope(model) {
return 'foo';
}
});
serviceFor uses the guid
as the id so that the same service instance is returned each time for the same object.
Again this can be changed by overriding contextualServiceID
, for example using the id
instead:
import ContextualServicesService from 'ember-contextual-services/services/contextual-service';
export default ContextualServicesService.extend({
contextualServiceID(model) {
return model.get('key');
}
});