eacp_webapp/htdocs/js/ol-airports.js

// DEPENDENCIES: moment.js, papaparse (for csv), lz-string (for compression)
var LSkey_airports = "ol_airports"
var LSkey_airports_lastupdate = "ol_airports-lastupdate"
var Airports = new Map();
function loadAirports(){
    console.log("loading airports");
    if(!needUpdatingAirports()){
        console.log("restoring airports");
        Airports = new Map(JSON.parse(LZString.decompress(localStorage.getItem(LSkey_airports))));
        if(Airports.size > 0) {return;} // map seemlingly has restored correctly, our work is done
    }

    var airports_csv_url = "data/airports.csv";

    Papa.parse(airports_csv_url, {
        download: true,
        header: true,
        skipEmptyLines: true,
        step: function(row) {

            row.data.forEach(function(tuple){

                if(tuple.type == "closed" || tuple.name.toLowerCase().includes("marked as spam")) return; // ignore closed or spam airports
                tuple.name = tuple.name.replace(/\s*Airport/ig, '').trim(); // remove obvious occurrence of airport in airport names

                var airportMeta = {
                    name: tuple.name,
                    iso_country: tuple.iso_country,
                    municipality: tuple.municipality
                };
                if(tuple.iata_code){
                    Airports.set(tuple.iata_code, tuple.ident); // save space in Localstorage: only save metainfo once, if IATA code given, need to re-loopup using the icao code given in the value of the kv pair
                }
                if(tuple.ident){
                    Airports.set(tuple.ident, airportMeta); // ident=ICAO id of airport
                }
            });
        },
        complete: function(){
            console.log("persisting airports");

            // persist map to LS
            localStorage.setItem(LSkey_airports, LZString.compress(JSON.stringify(Array.from(Airports.entries()))));
            localStorage.setItem(LSkey_airports_lastupdate, moment().toISOString()); // update "last updated"
        }
    });
}

function needUpdatingAirports(){
    var one_week_ago=moment().subtract(1,'week').toISOString();
    var lastupdate=localStorage.getItem(LSkey_airports_lastupdate);
    if(lastupdate){
        if(moment(lastupdate).isBefore(one_week_ago)){
            return true; // data is too old
        } else {
            return false; // data is fetched less than one week ago
        }
    } else {
        return true; // no date stored, fetch data to be sure
    }
}

function resolveAirportById(iata_or_icao){

    // since we store the meta info only for icao keys, we need to do indirection for IATA keys
    var airport_meta = Airports.get(iata_or_icao);
    var airport_icao = iata_or_icao; // by default, assume the parameter is already the ICAO
    if(typeof airport_meta === 'string'){ // value corr. to key is the icao code for the given IATA code
        airport_icao = airport_meta; // the value is our icao ID, so re-set the variable
        airport_meta = Airports.get(airport_icao); // lookup actual meta info to icao
    }

    if(airport_meta){
        var municipalityAddition = "";
        // if airport name already includes city name, don't add it, otherwise do
        if(!airport_meta.name.includes(airport_meta.municipality)){
            municipalityAddition = ", "+airport_meta.municipality;
        }
        return {
            text: airport_meta.name+municipalityAddition,
            label: '<a target="_blank" href="http://ourairports.com/airports/'+airport_icao+'">'+airport_meta.name+municipalityAddition+'</a>',
            applyFlag: function(htmlElement){ // set flag when it finished loading
                if($(htmlElement).hasClass("country-"+airport_meta.iso_country)) {
                    return; // if flag hasn't changed, don't re-request via HTTP
                }
                $.ajax({
                    url: "flags/4x3/"+airport_meta.iso_country.toLowerCase()+".svg",
                    success: function(rawsvg){
                        var svgElement = $(rawsvg);
                        if(!svgElement.get(0).classList) return; // some error occurred fetching svg
                        svgElement.get(0).classList.add("flag-icon"); // add class to new <svg> element (not possible via jquery)
                        $(htmlElement).html(svgElement);

                        // remove previous country class
                        $(htmlElement).removeClass(function(i,c) {
                            if(c){
                                return c.match(/country-\w+/gi).join(' ');
                            }
                        });
                        // add new country css attribute
                        $(htmlElement).addClass("country-"+airport_meta.iso_country); // save country info in class attribute
                    },
                    dataType: 'text'
                });
            }
        }
    } else {
        return {
            label: "",
            applyFlag: function(htmlElement){
                // remove svg
                $(htmlElement).html("");
                // remove country class
                $(htmlElement).removeClass(function(i,c) {
                    if(c){
                        return c.match(/country-\w+/gi).join(' ');
                    }
                });
            }
        }
    }
}