rdf-dataset-fragmenter/lib/transform/QuadTransformerBlankToFragment.js

Fragments an RDF dataset into multiple parts

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.QuadTransformerBlankToFragment = void 0;
const rdf_data_factory_1 = require("rdf-data-factory");
const DF = new rdf_data_factory_1.DataFactory();
/**
 * A quad transformer that maps BlankNodes to fragments on the subject URI,
 * based on the first subject that blank node appears with as an object.
 */
class QuadTransformerBlankToFragment {
    constructor() {
        this.mappings = {};
    }
    transform(quad) {
        if (quad.subject.termType === 'NamedNode' &&
            quad.object.termType === 'BlankNode' &&
            this.mappings[quad.object.value] === undefined) {
            const target = DF.namedNode(`${quad.subject.value.split('#')[0]}#${quad.object.value}`);
            this.mappings[quad.object.value] = target;
            return [DF.quad(quad.subject, quad.predicate, target, quad.graph)];
        }
        if (quad.subject.termType === 'BlankNode') {
            const target = this.mappings[quad.subject.value];
            if (target === undefined) {
                throw new Error(`Unmapped blank node: ${quad.subject.value}`);
            }
            return [DF.quad(target, quad.predicate, quad.object, quad.graph)];
        }
        return [quad];
    }
}
exports.QuadTransformerBlankToFragment = QuadTransformerBlankToFragment;
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