Velo coding / Dropdown menu not functioning

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import wixData from 'wix-data';

let lastFilterjobTitle;
let lastFilterlocation
let debounceTimer;

$w.onReady(() => {
    //STEP-1: Loading DropDown --> (LOCATIONS)
    loadLocations();
    
    //DropdDown-Change (LOCATIONS)
    $w('#iLocation').onChange(()=>{
        //selected VALUE...
        let myValue = $w('#iLocation').value;
        //Last filtered job-title??????? 
        //Where is it?
        //Ok, starting filtering function....
        filter(lastFilterjobTitle, myValue);
    });

    $w('#iTitle').onKeyPress((event)=>{
        if (debounceTimer) {
            clearTimeout(debounceTimer);
            debounceTimer = undefined;
        }
        debounceTimer = setTimeout(() => {
            filter($w('#iTitle').value, lastFilterlocation);  
        }, 500);
    });    
});


function filter(jobTitle, location) {
    // jobTitle = undefined!!!
    // and again cheking lasterFilteredJobTitle against current jobTitle?
    // Whats going on here?
    // Till here you never selected lastFilteredJobTitle !!!!
    // lastFilterjobTitle = undefined !!!!
    // jobTitle = undefined !!!!!
    if (lastFilterjobTitle !== jobTitle || lastFilterlocation !== location) {
        let newFilter = wixData.filter();
    
        if (jobTitle) {
            newFilter = newFilter.contains('jobTitle', jobTitle);
        }
        if (location) {
            newFilter = newFilter.contains('location', location);
            $w('#dataset13').setFilter(newFilter);
            lastFilterjobTitle = jobTitle; 
            lastFilterlocation = location;
        }
    }
}

function loadLocations() {
    wixData.query('location')
    .find()
    .then(res => {
        let options = [{"value": '', "label": 'All Location'}];
        options.push(...res.items.map(location => {
        return {"value": location.jobTitle, "label": location.jobTitle};
        }));
        $w('#iLocation').options = options;
    });
}