var _ = require('lodash'); // This middleware component trims the results array by granularity when // FallbackQuery was used. FallbackQuery is used for inputs like // `1090 N Charlotte St, Lancaster, PA` where the address may not exist and // we must fall back to trying `Lancaster, PA`. If the address does exist then // FallbackQuery will return results for: // - address+city+state // - city+state // - state // // Because the address matched, we're not interested in city+state or state, so // this component removes results that aren't the most granular. // layers in increasing order of granularity var layers = [ 'venue', 'address', 'street', 'neighbourhood', 'borough', 'postalcode', 'locality', 'localadmin', 'county', 'macrocounty', 'region', 'macroregion', 'dependency', 'country' ]; // this helper method returns `true` if every result has a matched_query // starting with `fallback.` function isFallbackQuery(results) { return results.every(function(result) { return result.hasOwnProperty('_matched_queries') && !_.isEmpty(result._matched_queries) && _.startsWith(result._matched_queries[0], 'fallback.'); }); } function hasRecordsAtLayers(results, layer) { return results.some(function(result) { return result._matched_queries[0] === 'fallback.' + layer; }); } function retainRecordsAtLayers(results, layer) { return results.filter(function(result) { return result._matched_queries[0] === 'fallback.' + layer; }); } function setup() { return function trim(req, res, next) { // don't do anything if there are no results or there are non-fallback.* named queries // there should never be a mixture of fallback.* and non-fallback.* named queries if (_.isUndefined(res.data) || !isFallbackQuery(res.data)) { return next(); } // start at the most granular possible layer. if there are results at a layer // then remove everything not at that layer. layers.forEach(function(layer) { if (hasRecordsAtLayers(res.data, layer )) { res.data = retainRecordsAtLayers(res.data, layer); } }); next(); }; } module.exports = setup;