doc/test/comunica/sparql_file/sparql-file1.mjs
2025-03-13 21:25:59 +03:00

44 lines
No EOL
1.4 KiB
JavaScript

// const QueryEngine = require('@comunica/query-sparql-file').QueryEngine;
import { QueryEngine } from '@comunica/query-sparql-file';
const myEngine = new QueryEngine();
const bindingsStream = await myEngine.queryBindings(`
SELECT ?s ?p ?o WHERE {
?s ?p <http://dbpedia.org/resource/Belgium>.
?s ?p ?o
} LIMIT 5`, {
sources: ['http://fragments.dbpedia.org/2015/en'],
});
// Consume results as a stream (best performance)
bindingsStream.on('data', (binding) => {
console.log(binding.toString()); // Quick way to print bindings for testing
console.log(binding.has('s')); // Will be true
// Obtaining values
console.log(binding.get('s').value);
console.log(binding.get('s').termType);
console.log(binding.get('p').value);
console.log(binding.get('o').value);
});
bindingsStream.on('end', () => {
// The data-listener will not be called anymore once we get here.
});
bindingsStream.on('error', (error) => {
console.error(error);
});
// Consume results as async iterable (easier)
for await (const binding of bindingsStream) {
console.log(binding.toString());
}
/*
// Consume results as an array (easier)
// console.log(bindings[0].get('s').value);
// TypeError: Cannot read properties of undefined (reading 'get')
const bindings = await bindingsStream.toArray();
console.log(bindings[0].get('s').value);
console.log(bindings[0].get('s').termType);
*/