@mathquis/modelx
v1.0.0
Published
API connected model and collection using Mobx
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ModelX
An API connected model and collection library using MobX v6
Installation
npm install -D @mathquis/modelx
Models
Create a model
A model is a set of attributes
import {Model, Collection} from '@mathquis/modelx';
// Create a model class
class User extends Model {
static get path() {
return '/app/{app.id}/users/{?id}';
}
// You can assign default values to the mode attributes
static get defaults() {
id: 0
lastName: '',
firstName: '',
email: '',
tags: []
}
}
const user = new User({
id: 1,
lastName: 'Doe',
firstName: 'John',
email: '[email protected]',
address: {
country: 'FR'
},
tags: ['a', 'b']
});
Accessing a model attributes
You can access a model attributes using the get()
method (using MobX observable magic) or accessing it directly on attributes
(directly as a Javascript object).
console.log(user.get('lastName')); // Outputs: "Doe"
console.log(user.get('unknownProperty')); // Output undefined
console.log(user.get('unknownProperty', 'defaultValue')); // Outputs: "defaultValue"
console.log(user.get(['address', 'country']); // Outputs: "FR"
Setting model attributes
To set a model attributes, use the set()
method.
// Set a single property
user.set('lastName', 'Smith');
console.log(user.get('lastName')); // Outputs: "Smith"
user.set(['address', 'country'], 'IT');
console.log(user.get('address.country')); // Outputs: "IT"
// Set multiple properties
user.set({
lastName: 'Jack',
firstName: 'Burton'
});
// Handling arrays
user.set('tags', ['c']);
// user.get('tags') will return ['c']
// Merge arrays
user.merge('tags', ['d']);
// user.get('tags') will return ['c', 'd']
// Handling objects
user.set('address', {street: 12});
// OR
user.set({address: {street: 12}});
// user.get('address') will return {street: 12} because the address attribute has been replaced
// Merging objects
user.merge('address', {street: 12}); // Shortcut for: user.set('address', {street: 12}, {merge: true});
// OR
user.merge({address: {street: 12}}); // Shortcut for: user.set({address: {street: 12}}, {merge: true});
// user.get('address') will return {country: 'FR', street: 12}
Checking if a model has an attribute
To check if a model has a specific attribute, use the has()
method.
user.has('email'); // Returns: true
user.has('unknown'); // Returns: false
Test an attribute
To check if an attribute contains a specific value you can use the is()
method.
user.is('email', '[email protected]'); // Returns: true
Validating attributes
You can validate a model's attributes at runtime using the validator
static getter. It must return a validation function that returns either true
or throw an Error
. If the attributes do not pass the validation, a ModelError
is thrown.
function validationFn(attributes: object): boolean {
if ( isNumber(attributes.id) ) return true;
throw new Error('Missing id attribute');
}
class ValidatedModel extends Model {
static get validator(): (attributes: object) => boolean {
return validationFn;
}
}
const model = new ValidatedModel(); // Throws ModelError
const model = new ValidatedModel({id: 1}); // This is fine
model.set('id', 'NotFine'); // Throws ModelError
Properties
A model has some usefull properties like isNew
(tells if the model has a non null id attribute), isDirty
(tells if the model's attributes has been modified since the last sync), isDestroyed
(tells if the model has been destroyed).
Collections
Collections are list of models. They provides lots methods to work on the models. Here are the supported methods:
set
, add
, remove
, clear
, getById
, removeById
, shift
, unshift
, pop
, push
, indexOf
, map
, reduce
, forEach
, pluck
, countBy
, filter
, every
, some
, find
, findById
, at
, first
, last
, shuffle
, distinct
, sortBy
, reverse
, clone
Create a collection
To create a collection, we need to define the type of model that the collection will accept. A collection accepts some options: comparator
to automatically sort the models and order
to define the sorting order (asc
or desc
).
import {Collection} from 'modelx';
const user1 = new User({id: 1, category: 'food'});
const user2 = new User({id: 2, category: 'movie'});
const user3 = new User({id: 3, category: 'food'});
const list = new Collection( User, [user1, user2, user3], {comparator: 'id', order: 'asc'});
list.forEach((model) => {
console.log(model.id);
});
// Outputs:
// 1
// 2
// 3
list.pluck('category'); // Returns: ['food', 'movie', 'food']
Virtual collection
Virtual collection are a subset of a collection. A collection and its virtual collections automatically stay in sync.
const virtualList = list.createVirtualCollection((model) => model.is('category', 'food'));
virtualList.forEach((model) => {
console.log(model.id);
});
// Outputs:
// 1
// 3
You can unsubscribe the virtual collection from its source with its cancelSubscription()
method.
virtualList.cancelSubscription();
Once unsubscribed, the virtual collection will not be kept in sync with the source collection but its models will still be shared between both collections.
Extending a collection
You can create more advanced collections by extending the default Collection.
import {Collection} from 'modelx';
export default class PagedCollection extends Collection {
public offset: number = 0;
public limit: number = 10;
public total: number = 0;
protected prepareListOptions(options: object) {
options = super.prepareListOptions(options);
options.offset = this.offset = options.offset || this.offset;
options.limit = this.limit = options.limit || this.limit;
return options;
}
protected onListSuccess(results){
this.total = results.total;
return super.onListSuccess(results);
}
}
Connectors
Connectors allow models and collections to interact with an API (http
, levelDB
, localStorage
, etc.). ModelX does not come with predefined connectors. You will have to write it yourself. All models and collection have isLoading
and isLoaded
properties reacting to connector requests.
Creating a connector
A connector implements a list of specific methods: list()
(get a list of models), fetch()
(get a model), save()
(persist a model), destroy()
(unpersist a model). Here is an example of a simple HTTP JSON connector.
import {Model, Collection, Connector, ConnectorResult, ConnectorResults} from 'modelx';
import Axios,{AxiosInstance} from 'axios';
export default class JsonApiConnector extends Connector {
private client: AxiosInstance;
initialize() {
this.client = Axios.create({
headers: {
'Accept': 'application/json'
},
responseType: 'json'
});
}
// Collection methods
list(collection: Collection, options: object = {}): Promise<ConnectorResults> {
this.onConnect();
return this.client( collection.path, {
...options,
method: 'get'
}).then((response) => {
this.onDisconnect();
return new ConnectorResults(response.data, response);
})
.catch((err) => {
this.onDisconnect();
throw err;
});
}
// Model methods
fetch(model: Model, options: object = {}): Promise<ConnectorResult> {
this.onConnect();
return this.client( model.path, {
...options,
method: 'get'
}).then((response) => {
this.onDisconnect();
return new ConnectorResult(response.data, response);
})
.catch((err) => {
this.onDisconnect();
throw err;
});
}
save(model: Model, attributes: object, options: object = {}): Promise<ConnectorResult> {
this.onConnect();
return this.client( model.path, model.untransform(), {
...options,
method: model.id ? 'put' : 'post',
data: attributes
}).then((response) => {
this.onDisconnect();
return new ConnectorResult(response.data, response);
})
.catch((err) => {
this.onDisconnect();
throw err;
});
}
destroy(model: Model, options: object = {}): Promise<ConnectorResult> {
this.onConnect();
return this.client( model.path, {
...options,
method: 'delete'
}).then((response) => {
this.onDisconnect();
return new ConnectorResult(model.attributes, response);
})
.catch((err) => {
this.onDisconnect();
throw err;
});
}
}
Once the connector is defined. We can create a model that will use it. Collections using this model will use the connector defined on the model.
import {Model, Collection} from 'modelx';
import {JsonApiConnector} from './jsonApiConnector';
const jsonApiClient = new JsonApiConnector();
class User extends Model {
static get connector(): Connector {
return jsonApiClient;
}
}
// We create a new User model
const user = new User({
id: 1,
lastName: 'Doe',
firstName: 'John'
});
user.save()
.then((model: Model) => {
// My model is now created on the API
return model.destroy();
})
.then((model: Model) => {
// My model is now deleted from the API
});
const users = new Collection( User );
users.list().then((collection: Collection) => {
console.log(collection.length);
});
Transforming model attributes
The attributes received from the connector can be manipulated using the model transform()
method. The model will provide attributes returned by its untransform()
method to the connector save()
method.
class MappedUser extends User {
protected transform(attributes: any): object {
return {
id: attributes._id,
familyName: attributes.lastName,
firstName: attributes.firstName
};
}
protected untransform(): object {
return {
_id: this.id,
lastName: this.attributes.familyName,
firstName: this.attributes.firstName
}
}
}