alcaeus/ResourceRepresentation.js

Hydra Core hypermedia-aware client library

import { rdf, hydra } from '@tpluscode/rdf-ns-builders';
export default class {
    constructor(graph, env, rootResource) {
        this.env = env;
        this.__graph = graph;
        this.__factory = env.rdfine().factory;
        this.rootNode = graph.node(rootResource);
        this.__uniqueResources = (() => {
            let map;
            return () => {
                if (!map) {
                    map = this.__graph.in().toArray()
                        .reduce((uniq, pointer) => {
                        if (!uniq.has(pointer.term)) {
                            return uniq.set(pointer.term, this._createEntity(pointer));
                        }
                        return uniq;
                    }, env.termMap());
                }
                return map;
            };
        })();
    }
    get(uri, { allObjects = false } = {}) {
        const pointer = this.__graph.namedNode(decodeURI(uri));
        const isSubject = pointer.out().terms.length > 0;
        const isObjectAndAllowedToReturn = allObjects && pointer.in().terms.length;
        if (!isSubject && !isObjectAndAllowedToReturn) {
            return undefined;
        }
        return this.__factory.createEntity(pointer);
    }
    get root() {
        const collectionNode = this.rootNode.in(hydra.view);
        if (collectionNode.term) {
            return this.__factory.createEntity(collectionNode);
        }
        return this.__factory.createEntity(this.rootNode);
    }
    get length() {
        return this.__uniqueResources().size;
    }
    ofType(classId) {
        const type = typeof classId === 'string' ? this.env.namedNode(classId) : classId;
        return this.__graph.has(rdf.type, type).map(r => this._createEntity(r));
    }
    [Symbol.iterator]() {
        return this.__uniqueResources().values();
    }
    _createEntity(node) {
        return this.__factory.createEntity(node);
    }
}