Dynamic Programming: return all matched data in JavaScript

Suppose we have a JSON object that have information about the location of some cities of some countries like this −
const countryInfo = {
   country: [{
      name: "Bangladesh",
      province: [{
         name:"Dhaka",
         city: [{
            name:"Tangail",
            lat: '11'
         }, {
            name:"Jamalpur",
            lat: '12'
         }]
      }, {
         name: "Khulna",
         city: [{
            name:"Jossore",
            lat: '22'
         }, {
            name:"Tangail",
            lat: '23'
         }]
      }, {
         name: "Rajshahi",
         city: [{
            name:"Pabna",
            lat: '33'
         }, {
            name:"Rangpur",
            lat: '33'
         }]
      }]
   },{
      name: "India",
      province: [{
         name:"West Bengal",
         city: [{
            name:"Calcutta",
            lat: '111'
         }, {
            name:"Tangail",
            lat: '112'
         }]
      }, {
         name: "Uttar Pradesh",
         city: [{
            name:"Agra",
            lat: '122'
         }, {
            name:"Tajmahal",
            lat: '123'
         }]
      }, {
         name: "Rajasthan",
         city: [{
            name:"Kanpur",
            lat: '131'
         }, {
            name:"Jaypur",
            lat: '132'
         }]
      }]
   }]
};
We are required to write a JavaScript function that takes in one such object and a search string.
We should then search all the city names matching the search string and return an array of all the city objects that match the query.
The code for this will be −
const countryInfo = {
   country: [{
      name: "Bangladesh",
      province: [{
         name:"Dhaka",
         city: [{
            name:"Tangail",
            lat: '11'
         }, {
            name:"Jamalpur",
            lat: '12'
         }]
      }, {
         name: "Khulna",
         city: [{
            name:"Jossore",
            lat: '22'
         }, {
            name:"Tangail",
            lat: '23'
         }]
      }, {
         name: "Rajshahi",
         city: [{
            name:"Pabna",
            lat: '33'
         }, {
            name:"Rangpur",
            lat: '33'
         }]
      }]
   },{
      name: "India",
      province: [{
         name:"West Bengal",
         city: [{
            name:"Calcutta",
            lat: '111'
         }, {
            name:"Tangail",
            lat: '112'
         }]
      }, {
         name: "Uttar Pradesh",
         city: [{
            name:"Agra",
            lat: '122'
         }, {
            name:"Tajmahal",
            lat: '123'
         }]
      }, {
         name: "Rajasthan",
         city: [{
            name:"Kanpur",
            lat: '131'
         }, {
            name:"Jaypur",
            lat: '132'
         }]
      }]
   }]
};
const searchForCity = (obj, query) => {
   const cities = obj.country.reduce((acc, val) => {
      val.province.forEach(el => {
         el.city.forEach(elm => {
            acc.push(elm);
         });
      });
      return acc;
   },[]);
   const res = cities.filter(el => {
      return el.name === query;
   });
   return res;
};
console.log(searchForCity(countryInfo, 'Tangail'));
The output in the console −
[
   { name: 'Tangail', lat: '11' },
   { name: 'Tangail', lat: '23' },
   { name: 'Tangail', lat: '112' }
]