Autocomplete filtered with mongodb - node.js

Question

I would like to perform autocompletion on the name but filtered on a specific city with mongoose and nodejs.
I have a mongodb collection like this :
{
"_id" : ObjectId("6007fd9d984e2507ad452cf3"),
"name" : "John",
"city" : "A",
},
{
"_id" : ObjectId("6007ff6844d9e517e1ec0976"),
"name" : "Jack",
"city" : "B",
}
What i have done so far :
I have setup MongoDB Atlas with a Search Index (with the help of search doc)
And set up the autocomplete like that :
router.get('/search', async (request, response) => {
try {
let result = await Client.aggregate([
{
"$search": {
"autocomplete": {
"query": `${request.query.term}`,
"path": "name",
"fuzzy": {
"maxEdits": 2,
"prefixLength": 3,
},
},
},
},
{
$limit: 3
},
{
$project: {
"_id": 0,
}
}
]);
response.send(result);
} catch (e) {
response.status(500).send({message: e.message});
}
});
In front-end, with autocompleteJs :
const autoCompleteJS = new autoComplete({
data: {
src: async () => {
const query = document.querySelector("#autoComplete").value;
const source = await fetch(`${window.location.origin}/search?term=${query}`);
const data = await source.json();
return data;
},
key: ["name"],
},
trigger: {
event: ["input", "focus"],
},
searchEngine: "strict",
highlight: true,
});
So far it is working well. But I don't know how to make the autocomplete result filtered based on city. It seems that the documentation does not mention this. Do you have any leads.

Answer 1

Use the $where pipeline stage from the aggregation pipeline after performing your search to filter out unwanted documents. So for example,
Client.aggregate([
{
"$search": {
"autocomplete": {
"query": `${request.query.term}`,
"path": "name",
"fuzzy": {
"maxEdits": 2,
"prefixLength": 3,
},
},
},
},
{
$match: { city: 'city-name' }
},
{
$limit: 3
},
{
$project: {
"_id": 0,
}
}
]);

Answer 2

Use a compound operator like so which lets you have more control over your results in a performant fashion:
"$search": {
"compound" : {
"filter" : [{
"text" : { path: "city", query: "New York" }
}],
"must": [{
"autocomplete": {
"query": `${request.query.term}`,
"path": "name",
"fuzzy": {
"maxEdits": 2,
"prefixLength": 3,
},
},}
}] }
using filter will filter your results, without impacting the score. must will require that the name field will also match. Also take a look at should and mustNot in the compound docs for more options.