moddle


A utility library for working with meta-model based data structures.

What is it good for?

moddle offers you a concise way to define meta models in JavaScript. You can use these models to consume documents, create model elements, and perform model validation.

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You start by creating a moddle schema. It is a JSON file which describes types, their properties, and relationships:

``json
{
"$schema": "https://unpkg.com/moddle/resources/schema/moddle.json",
"name": "Cars",
"uri": "http://cars",
"prefix": "c",
"types": [
{
"name": "Base",
"properties": [
{ "name": "id", "type": "String", "isAttr": true }
]
},
{
"name": "Root",
"superClass": [ "Base" ],
"properties": [
{ "name": "cars", "type": "Car", "isMany": true }
]
},
{
"name": "Car",
"superClass": [ "Base" ],
"properties": [
{ "name": "name", "type": "String", "isAttr": true, "default": "No Name" },
{ "name": "power", "type": "Integer", "isAttr": true },
{ "name": "similar", "type": "Car", "isMany": true, "isReference": true },
{ "name": "trunk", "type": "Element", "isMany": true }
]
}
]
}
`

You may attach the provided JSON schema to get your moddle descriptor validated by code editor.

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You can instantiate a moddle instance with a set of defined schemas:

`javascript
import { Moddle } from 'moddle';

var cars = new Moddle([ carsJSON ]);
`

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Use a moddle instance to create objects of your defined types:

`javascript
var taiga = cars.create('c:Car', { name: 'Taiga' });

console.log(taiga);
// { $type: 'c:Car', name: 'Taiga' };


var cheapCar = cars.create('c:Car');

console.log(cheapCar.name);
// "No Name"


// really?
cheapCar.get('similar').push(taiga);
`

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Then again, given the knowledge moddle has, you can perform deep introspection:

`javascript
var carDescriptor = cheapCar.$descriptor;

console.log(carDescriptor.properties);
// [ { name: 'id', type: 'String', ... }, { name: 'name', type: 'String', ...} ... ]
`

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moddle is friendly towards extensions and keeps unknown _any_ properties around:

`javascript
taiga.set('specialProperty', 'not known to moddle');

console.log(taiga.get('specialProperty'));
// 'not known to moddle'
`

It also allows you to create _any_ elements for namespaces that you did not explicitly define:

`javascript
var screwdriver = cars.createAny('tools:Screwdriver', 'http://tools', {
make: 'ScrewIt!'
});

car.trunk.push(screwdriver);
``

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Have a look at our test coverage to learn about everything that is currently supported.

Resources

* Issues
* Examples
* Documentation

Related

* moddle-xml: read xml documents based on moddle descriptors

License

MIT