itowns/lib/Provider/DataSourceProvider.js

A JS/WebGL framework for 3D geospatial data visualization

export default {
  executeCommand(command) {
    const layer = command.layer;
    const src = command.extentsSource;
    const dst = command.extentsDestination || src;
    const promises = src.map((from, i) => layer.getData(from, dst[i]));

    // partialLoading sets the return promise as fulfilled if at least one sub-promise is fulfilled
    // It waits until all promises are resolved
    if (command.partialLoading) {
      return Promise.allSettled(promises).then(results => {
        const anyFulfilledPromise = results.find(promise => promise.status === 'fulfilled');
        if (!anyFulfilledPromise) {
          // All promises failed -> reject
          return Promise.reject(new Error('Failed to load any data'));
        }
        return results.map(prom => prom.value ? prom.value : null);
      });
    }

    // Without partialLoading, the return promise is rejected as soon as any sub-promise is rejected
    return Promise.all(promises);
  }
};