Function to chunk large geometry tables from PostGIS to GeoJSON

chunkGeoJson.js

  async createGeoJson(id, geom, srid, values) {
    try {
      const limit = 100000;
      let offset = 0;
      let features = [];
      while (true) {
        const chunk = await this.db.oneOrNone(sql.createGeoJson, {
          id: id,
          geom: geom,
          srid: srid,
          table: values,
          limit: limit,
          offset: offset
        });
        
        if (!chunk || !chunk.jsonb_build_object || !chunk.jsonb_build_object.features || chunk.jsonb_build_object.features.length === 0) {
          break;
        }

        const chunkFeatures = chunk.jsonb_build_object.features;
        features = features.concat(chunkFeatures);
        offset += limit;
      }

      const result = {
        type: 'FeatureCollection',
        features
      };

      console.debug(`result: ${JSON.stringify(result)}`);
      return result;
    } catch (error) {
      console.error('Error in createGeoJson:', error);
      throw error;
    }
  }