JSFiddle - React, Tailwind, and code Playground

JavaScript

var Model = function() { 
   this.names = ["name1", "name2"]; 
}

Model.prototype.init = function(item_name) {
    this.names[0] = item_name;
}
var Item = new Model();
Item.init("New Name"); // ERROR: Cannot set property '0' of undefined

console.log(i);