JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="Test">
    <div ng-controller="TestController">
        <div ng-repeat="str in myData">
            <input type="text" ng-model="str.string" ng-change="click()">
        </div>
        <br/> <span ng-if="count >= 1" style="color:red;">One or more string is empty</span>

    </div>
</div>
</div>

JavaScript

var app = angular.module('Test', []);

app.controller('TestController', ['$scope', function ($scope) {

    $scope.myData = [{
        "id": 1,
            "string": "A"
    }, {
        "id": 2,
            "string": ""
    }, {
        "id": 3,
            "string": "M"
    }];

    showVal();
    $scope.click = function () {
        showVal();
    }

    function showVal() {
        $scope.count = 0;
        for (var i = 0; i < $scope.myData.length; i++) {
            if ($scope.myData[i].string === "") {
                $scope.count++;
            }
        }
    }


}]);