node.js - how to query nested arrays in mongoose -

i have schema this

'use strict';  var mongoose = require('mongoose'); var schema = mongoose.schema;  var teacherschema = new schema({     education: [{degree: string, institutename: string}],     dob: date,     photourl: string,     phonenumber: string,     institutes: [{type: mongoose.schema.objectid, ref: 'institute'}],     subjects: [{         name: string,         topics: [{             name: string,             modules: [{                 name: string,                 classes: [{                     name: string,                     starttime: date,                     endtime: date,                     fee: number                 }]             }]         }]     }],     created: {type: date, default: date.now} })  module.exports = mongoose.model('teacher', teacherschema); 

my question how can query in nested arrays? specific lets want find teachers have @ least 1 subject/topic/module/class name starts "math". how can mongoose?

see if works...

db.teacher.find({$or: [{'subjects':{"$elemmatch":{'name':'math'}}}, {'subjects.topics':{"$elemmatch":{'name':'math'}}}, {'subjects.topics.modules.classes':{"$elemmatch":{'name':'math'}}}] }) 

however, curious know why modules array needed when contains classes array?

let's want search wildcard "ath"

db.stack30173606.find({$or: [ {'subjects':{"$elemmatch":{'name':'math'}}},  {'subjects.topics':{"$elemmatch":{'name':'math'}}},  {'subjects.topics.modules':{"$elemmatch":{'name':'math'}}},  {'subjects.topics.modules.classes.name':{"$in":[/math/]}} ] }) 

for case insensitive, check this: how make case-insensitive queries on mongodb?