JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" type="text/css" href="//cdn.sencha.io/ext-4.1.0-gpl/resources/css/ext-all-debug.css"
/>

JavaScript

/* WITH total_students IN UNIVERSITY MODEL */

Ext.define("University", {
    extend: 'Ext.data.Model',
    fields: [
        'uni_id', 'uni_name', 'openingYear', 'total_students'],

    /* Relation with Student Model */
    hasMany: {
        model: 'Student',
        name: 'students'
    },
});

Ext.define("Student", {
    extend: 'Ext.data.Model',
    fields: [
        'stud_id', 'stud_name']
});


var data = [
       {
        "uni_id": 1,
            "uni_name": "Gujarat University",
            "openingYear": 1980,
            "students": [{
            "stud_id": 1,
                "stud_name": "Rishabh Shah"
        }, {

            "stud_id": 2,
                "stud_name": "Rakesh Prajapati"
        }, {

            "stud_id": 3,
                "stud_name": "Vaibhavi Shah"
        }, {

            "stud_id": 4,
                "stud_name": "Jitu Mishra"
        }, {

            "stud_id": 5,
                "stud_name": "Sonu Nigam"
        }, {

            "stud_id": 6,
                "stud_name": "K.K."
        }, {

            "stud_id": 7,
                "stud_name": "Amitabh Bachan"
        }]
    }, {
        "uni_id": 2,
            "uni_name": "Saurastra University",
            "openingYear": 1985,
            "students": [{

            "stud_id": 1,
                "stud_name": "Rakhi Sawant"
        }, {

            "stud_id": 2,
                "stud_name": "Smit Patel"
        }, {

            "stud_id": 3,
                "stud_name": "Kashyap Thaker"
        }]
    }, {
        "uni_id": 3,
            "uni_name": "North Gujarat University",
            "openingYear": 1989,
            "students": [{

            "stud_id": 1,
                "stud_name": "Angellina Jollie"
        }, {

            "stud_id": 2,
                "stud_name": "Parag Raval"
        }, {

            "stud_id": 3,
                "stud_name": "Harshal Patel"
        }, {

            "stud_id": 4,
                "stud_name": "Harsha Bhogle"
    ...