How to query objects with property contains a value in loopback - loopbackjs

Question

I have a model event which referenceMany user.
"relations": {
"attendees": {
"type": "referencesMany",
"model": "user",
"foreignKey": "attendeeIds",
"options": {
"validate": true,
"forceId": false,
"persistent": true
}
}
How can I query event which attendees property contain a given value? attendees is an array containing userId.
For example:
Event.find({
where: {
attendees: {
contains: givenUserId
}
}
}
)

Answer 1

This feature is called 'Filter on level 2 properties' as referenced here and is being implemented for Memory and MongoDB connectors. It still has some issues.
For SQL connectors, this isn't supported yet and - as mentioned also inside this open discussion link - it requires some time which cannot be afforded now.
Possible work around here with regexp that would apply to the underlying JSON string and executing SQL directly via datasource.connector.execute()
Simple implementaion could be:
AnyModel.getApp((err, app) => {
if (err) {
console.log(err);
next(err);
}
// Using MySQL
const MySQL = app.dataSources.MySQL;
MySQL.connector.execute(`select * from Table where column like '%${string}%'`,
[], {}, (err, data) => {
if (err) {
console.log(err);
next(err);
}
console.log(data);
next();
});
});