How can I only get the XML child element if it exists except getting the child of the next parent?

Question

I'm trying to figure out how I can get the XML child element of the current parent element. Right now if I try to get the current child element, if it doesn't exist I just get the next element with this name except an empty result...

I already tried to get all children of this parent element but didn't find any way how to do this...

Currently, my code looks like this:

 x = xmlDoc.getElementsByTagName('place');
    for (i = 0; i < (x.length - 1)  ;) { 
        type = x[i].getAttribute('type');
        console.warn("Typ: " + type);
            xname = xmlDoc.getElementsByTagName(type);
            name = xname[i].childNodes[0].nodeValue;
            txt += name + "<br>";
            xroad = xmlDoc.getElementsByTagName("road");
            road = xroad[i].childNodes[0].nodeValue;
            txt += road + " ";
            xnum = xmlDoc.querySelectorAll("house_number");
            num = xnum[i].childNodes[0].nodeValue;
            txt += num + "<br>";

The XML I'm referring to, or at least parts of it look like this:

<place place_id="57293627" osm_type="node" osm_id="4605575366" place_rank="30" boundingbox="48.8344591,48.8345591,8.2877028,8.2878028" lat="48.8345091" lon="8.2877528" display_name="Rheinau-Bäck, Murgtalstraße, Bischweier, Nachbarschaftsverband Bischweier-Kuppenheim, Landkreis Rastatt, Regierungsbezirk Karlsruhe, Baden-Württemberg, 76476, Deutschland" class="shop" type="bakery" importance="0.001" icon="https://nominatim.openstreetmap.org/images/mapicons/shopping_bakery.p.20.png">
    <extratags>
        <tag key="opening_hours" value="Mo-Sa 06:00-20:00"/>
    </extratags>
    <bakery>Rheinau-Bäck</bakery>
    <road>Murgtalstraße</road>
    <village>Bischweier</village>
    <county>Nachbarschaftsverband Bischweier-Kuppenheim</county>
    <state_district>Regierungsbezirk Karlsruhe</state_district>
    <state>Baden-Württemberg</state>
    <postcode>76476</postcode>
    <country>Deutschland</country>
    <country_code>de</country_code>
</place>
<place place_id="239017" osm_type="node" osm_id="52623297" place_rank="30" boundingbox="48.9310367,48.9311367,8.2681663,8.2682663" lat="48.9310867" lon="8.2682163" display_name="Maier Bäck, 63, Hauptstraße, Durmersheim, Verwaltungsverband Durmersheim, Landkreis Rastatt, Regierungsbezirk Karlsruhe, Baden-Württemberg, 76448, Deutschland" class="shop" type="bakery" importance="0.001" icon="https://nominatim.openstreetmap.org/images/mapicons/shopping_bakery.p.20.png">
    <extratags>
        <tag key="wheelchair" value="yes"/>
        <tag key="contact:phone" value="+49 7245 2338"/>
    </extratags>
    <bakery>Maier Bäck</bakery>
    <house_number>63</house_number>
    <road>Hauptstraße</road>
    <town>Durmersheim</town>
    <county>Verwaltungsverband Durmersheim</county>
    <state_district>Regierungsbezirk Karlsruhe</state_district>
    <state>Baden-Württemberg</state>
    <postcode>76448</postcode>
    <country>Deutschland</country>
    <country_code>de</country_code>
</place>

As you can see, only the second place has a <house_number> tag. If I would use my code with this XML file, I would get the house number 63 for the first element and no house number for the second element. It's like if the parent XML doesn't contain a "house_number" element, it just picks the next one it finds - some parent elements later...

I hope I explained it clear enough and I hope it's no duplicate but I didn't find anything and I have literally no idea how I could do this by myself...

Thanks in advance

Niko

Answer 1

The basic problem is you query the whole document inside your loop for child tags of <place>

Therefore the indexing of those full document queries won't match the indexing of <place> used in your loop since there could be more or less of the nested tags

Instead, query within each place instance so a query like:

xnum = xmlDoc.querySelectorAll("house_number");

Would be more like

xnum = x[i].querySelector("house_number");
if(xnum ){
    num = xnum.childNodes[0].nodeValue;
}