@typemf/json

JSON serialization for @typemf/core.

Installation

npm install @typemf/core @typemf/json

Usage

registerJsonFormat registers the format for the json file extension:

import { ResourceSetImpl, URI } from '@typemf/core';
import { registerJsonFormat } from '@typemf/json';
import { NodeFileUriConverter } from '@typemf/node';

const resourceSet = new ResourceSetImpl();
resourceSet.getUriConverterRegistry().register(new NodeFileUriConverter());
registerJsonFormat(resourceSet.getResourceFactoryRegistry());
resourceSet.getPackageRegistry().register(LibraryPackageImpl.eINSTANCE);

const resource = await resourceSet.getResource(URI.createFileURI('/path/to/library.json'), true);

The EPackage of every namespace used in the file must be in the package registry before loading.

Format

{
  "$namespaces": { "library": "https://example.org/library" },
  "$roots": [
    {
      "$eClass": { "namespace": "library", "name": "Library" },
      "name": "City Library",
      "writers": [{ "$eClass": { "namespace": "library", "name": "Writer" }, "name": "Frank Herbert" }],
      "books": [
        {
          "$eClass": { "namespace": "library", "name": "Book" },
          "title": "Dune",
          "pages": 412,
          "author": { "$ref": "#Writer_Frank Herbert" }
        }
      ]
    }
  ]
}

• $namespaces maps prefixes to nsURIs; $eClass names a class by prefix and name.
• $roots holds the root objects. A document may have several.
• Contained objects are nested. Other references are { "$ref": "..." }:
  • #<id>: an object in the same document, by ID
  • #/0/books/2: an object in the same document, by position (for classes without an ID attribute)
  • <uri>#<id or position>: an object in another document, loaded on demand
• A $ref carries $eClass only when the target's class differs from the declared type of the reference.
• EDate values are ISO 8601 strings.

References between JSON and XMI documents work in both directions.

License

Apache-2.0