JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/knockout/3.0.0/knockout-min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/knockout.mapping/2.3.5/knockout.mapping.js"></script>
<h3>Diagnosis Codes<input type="button" value="Add" data-bind="click:AddDiagnosisCode"/></h3>
<div data-bind="foreach:DiagnosisCodes">
    <div><input type="text"  data-bind="value:value, focusOnCreate:isNew()"/>
    </div>
</div>

JavaScript

var Record = function(value, isNew){
    var self = this;
    self.value = ko.observable(value);
    self.isNew = ko.observable(isNew || false);
}

var VM = function() {
    var self = this;    
    self.DiagnosisCodes = ko.observableArray([
        new Record("2345"),
        new Record("6789")]);
    self.enableFocus = ko.observable(true);
    self.AddDiagnosisCode = function(){
        self.DiagnosisCodes.push(new Record("", true));
    }
}

ko.bindingHandlers.focusOnCreate = {
    init:function(element, valueAccessor, allBindings, viewModel, bindingContext) {
        if(valueAccessor()){
            $(element).focus();
        }
    }
}
    
     ko.applyBindings(new VM());