@windingtree/wt-search-api/src/services/query-parser/indices/by-location.js

NodeJS app that enables quick search over data from Winding Tree platform

const { QueryParseError } = require('../errors');

const MAX_DISTANCE = 200; // Disallow large distances as they break the approximation.

/**
 * Extract location query from the params.
 *
 * @param {Object} query request GET params
 * @return {Array}
 * @throw QueryParseError
 *
 */
function getFilter (filters) {
  if (!(filters instanceof Array)) {
    filters = [filters];
  }
  return filters.map((filter) => {
    let [coords, distance] = filter.split(':'),
      [lat, lng] = coords.split(',');
    [distance, lat, lng] = [distance, lat, lng].map((x) => Number(x));
    if ((isNaN(distance) || isNaN(lat) || isNaN(lng)) ||
        (lat < -90 || lat > 90) ||
        (lng < -180 || lng > 180) ||
        (distance < 0)) {
      throw new QueryParseError(`Invalid location filter ${filter}.`);
    }
    if (distance > MAX_DISTANCE) {
      throw new QueryParseError(`Maximum allowed distance in a filter is ${MAX_DISTANCE} km`);
    }
    return {
      type: 'location',
      condition: { lat: lat, lng: lng, distance: distance },
    };
  });
}

/**
 * Extract location query from the params.
 *
 * @param {Object} query request GET params
 * @return {Object}
 * @throw QueryParseError
 *
 */
function getSort (sort) {
  if (sort instanceof Array) {
    throw new QueryParseError('Only one distance-based sort can be specified at once.');
  }
  const [lat, lng] = sort.split(',').map((x) => Number(x));
  if ((isNaN(lat) || isNaN(lng)) ||
      (lat < -90 || lat > 90) ||
      (lng < -180 || lng > 180)) {
    throw new QueryParseError(`Invalid sorting criteria: ${sort}.`);
  }
  return {
    type: 'distance',
    data: { lat: lat, lng: lng },
  };
}

module.exports = {
  getFilter,
  getSort,
  MAX_DISTANCE,
};