Using a structured query to fetch values based on key in array - google-cloud-firestore

Question

In my firestore I have a document structured as shown below.
I am trying to set up a Zapier Zap that will allow me to fetch the store name, based on the storeId. It requires a JSON structured query that fetches the data.
Is it possible to do, and where should I begin, I find the documentation lacking examples. The only query I have right now is as shown below, but obviously, it does not work since all data is in a single document.
"where": {
"fieldFilter": {
"field": {
"fieldPath": "stores/*/storeId"
},
"op": "EQUAL",
"value": {
"stringValue": "def"
}
}
}
Document structure
{
"stores": {
"0": {
"storeId": "abc",
"name": "Store 1"
},
"1": {
"storeId": "def",
"name": "Store 2"
}
}
}

Answer 1

I don't think you can do this with an array field, but you can if you change that array to a map field. Something like this:
mycollection/mydoc
{
"someotherfield": "foo",
"stores": {
"abc": {
"name": "Store 1"
},
"def": {
"name": "Store 2"
}
}
}
Now you can use a field mask:
GET https://firestore.googleapis.com/v1/projects/MY-PROJECT/databases/(default)/documents/mycollection/mydoc?mask.fieldPaths=stores.abc.name
Response:
{
"name": "projects/MY-PROJECT/databases/(default)/documents/mycollection/mydoc",
"fields": {
"stores": {
"mapValue": {
"fields": {
"abc": {
"mapValue": {
"fields": {
"name": {
"stringValue": "Store 1"
}
}
}
}
}
}
}
},
"createTime": "2019-04-20T19:14:01.792855Z",
"updateTime": "2019-04-22T18:07:05.660561Z"
}