country-in-text-detector/index.js

Module for detection of countries in given text. Detects countries by international and local name, some of them in more language mutations. Uses also names of large cities to derive related countries.

var io = require("./lib/io.js");
var COUNTRIES = io.loadCoutries();
var CITIES = io.loadCities();

function deletePrePostfixes(arr1, arr2){
	var lastJ = 0;
	for(var i = 0; i < arr1.length; i++){
		for(var j = lastJ; j < arr2.length; j++){
			if(arr1[i].length > arr2[j].length && (arr1[i].startsWith(arr2[j]) || arr1[i].endsWith(arr2[j]))){
				arr2.splice(j, 1);
				lastJ = j;
				i++;
				break;
			}
			if(arr1[i].length < arr2[j].length && (arr2[j].startsWith(arr1[i]) || arr2[j].endsWith(arr1[i]))){
				arr1.splice(i, 1);
				lastJ = j;
				i++;
				break;
			}
		}
	}
}

function detect(str) {
	var clean = " " + io.cleanFromSpecials(str);
	var result = [];
	for(var i = 0; i < COUNTRIES.length; i++){
		if(typeof COUNTRIES[i].string_match === "undefined" || COUNTRIES[i].string_match === null){continue;}
		var matches = clean.match(COUNTRIES[i].string_match);
		if(!(typeof matches === "undefined" || matches === null)) {
			matches = matches.map(function(m){return m.substring(1);});
			result.push({
				iso3166: COUNTRIES[i]["country_iso_3166-1_alpha-2"],
				name: COUNTRIES[i].country_name,
				type: "country",
				matches: matches
			});
		}
	}

	for(var i = 0; i < CITIES.length; i++){
		var matches = clean.match(CITIES[i].string_match);
		if(!(typeof matches === "undefined" || matches === null)) {
			matches = matches.map(function(m){return m.substring(1);});
			result.push({
				iso3166: CITIES[i]["country_iso_3166-1_alpha-2"],
				name: CITIES[i].city_name,
				countryName: CITIES[i].country_name,
				type: "city",
				matches: matches
			});
		}
	}

	// fallback for prefixes / postfixes
	// if two results A and B have same name and same type
	// and one of them (A) has match that is prefix of match of the other one (B)
	// remove the shorter match (prefix)
	for(var i = 0; i < result.length;i++){
		for(var j = i+1; j < result.length;j++){
			if(result[i].name == result[j].name && result[i].type == result[j].type){
				deletePrePostfixes(result[i].matches, result[j].matches);
			}
		}
	}

	result = result.filter(function(r){return r.matches.length;});

	return result;
}

module.exports.detect = detect;