Restrict suggestions in Algolia to postcode - filtering

Question

In Algolia Places I want to restrict the suggestions for streets to a specific postcode. I cannot seem to get it to work however. I thought this might be how it's done, but it doesn't work.
const optionsStreet = {
appId: '...',
apiKey: '...',
container: document.querySelector('#address'),
templates: {
value: function (suggestion) {
return suggestion.name;
}
}
};
const configStreet = {
language: 'de', // Receives results in German
postcodes: ['12345'],
type: 'address'
};
const placesStreet = places(optionsStreet).configure(configStreet);
placesStreet.on('change', function resultSelected(e) {
document.querySelector('#address').value = e.suggestion.name || '';
});

Answer 1

There's no easy way to do what you want.
You might want to open a feature request!
In the meantime...
First option
If that's some data you can get, use the insidePolygon option to restrict the searches to the geographical area represented by the postcode(s) you're interested in.
Note that you can filter on multiple disjoint polygons.
That option is a bit cumbersome to put in place but will give you the best results, as it ensures you'll get only the hits from the area you want.
Second option
You can also fork the project and fiddle with that part of the code:
.then(content => {
const hits = content.hits.map((hit, hitIndex) =>
formatHit({
formatInputValue: controls.formatInputValue,
hit,
hitIndex,
query,
rawAnswer: content,
})
);
controls.onHits({
hits,
query,
rawAnswer: content,
});
return hits;
})
Filter content.hits for the hits that match your postcode only and you'll get your filtered suggestions.
Two recommendations:
Increase the hitsPerPage setting because you're going to be removing many results from the hits due to your postcode filter:
const placesStreet = places(options).configure({
...config,
computeQueryParams(query) {
return {...query, hitsPerPage: 100};
}
});
You'll want to fine-tune the 100 depending on what you need.
Use the arountLatLng configuration to specify a point within the postcode area you want to target, to maximize the number of hits with the correct postcode.