how to compare two fields defined in schema($gte) in mongoose

Question

Food Schema

const mongoose = require('mongoose');

const Schema = mongoose.Schema;

const foodSchema = new Schema({
  foodName: {
    type: String,
    required: true
  },
  price: {
    type: String,
    required: true
  },
  offerPrice:{
    type: String,
    required: true
  },
  shopName: {
    type: String,
    required: true
  }
  
});

module.exports = mongoose.model('Food', foodSchema);

how to select the foods where food.price>food.offerPrice "price": { $gt: 100} this selects the food where the price is greater than 100 but i need to compare two values defined in schema "price": { $gt:offerPrice } is invalid syntax