Ways to verify if the length of a string is zero in Angular JS

An array was created and initialized with various fields, including targaauto. Within the add function, there is a check for an error alert if the length of the car plate is equal to 0. However, this functionality does not work correctly as the alert does not show up when the license plate is not entered. Various conditions were tried within the if statement in addition to the one defined in the code.

PROVEN CONDITIONS

if (cars.targaauto.length == 0)

if ($ cars.targaauto.length == 0)

if (targaauto.length == 0) 

START ANGULAR JS CODE

angular.module('tabelle', [])
.controller('test', function($scope){


$scope.cars =    [{id: "1", targaauto : "AR152FP", datiintestatario : "Maurizio Generosi", 
                 marca : 
                 "FIAT PUNTO", id_bottone: "1"},
                 {id: "2", targaauto  : "AR34512", datiintestatario : "Nicola Lops", marca : 
                 "TOYOTA YARIS", id_bottone: "2"},
                 {id: "3", targaauto : "BS25671", datiintestatario : "Sabrina 
                 De Martino", 
                 marca 
                 : "FIAT PANDA", id_bottone: "3"}];

$scope.aggiungi = function() {
    if($scope.cars.targaauto.length==0){
        alert("Errore! Inserire la targa");
    }
    $scope.cars.push({
    id: $scope.id,
    targaauto: $scope.targaauto,
    datiintestatario: $scope.datiintestatario,
    marca: $scope.marca,
    id_bottone: $scope.id_bottone
    })


    $scope.id = " ";
    $scope.targaauto = " ";
    $scope.datiintestatario = " ";
    $scope.marca = " ";
};


$scope.rigadaeliminare = function(indice) {
$scope.idcancellare = indice;

};
$scope.rimuovi = function () {
$scope.cars.splice($scope.idcancellare, 1);
};

//SELEZIONE INDICE DELLA RIGA DEL RECORD
function rigadamodificare(indice){
for(let i=0; i<$scope.cars.length;i++){
    if($scope.cars[i].id==indice){
        return i;
    }
}
return -1;
};

$scope.aggiorna = function(id) {
let index = rigadamodificare(id);
let i = $scope.cars[index];
$scope.id=i.id;
$scope.targaauto=i.targaauto;
$scope.datiintestatario=i.datiintestatario;
$scope.marca=i.marca;
};

$scope.salva = function() {
let index = rigadamodificare($scope.id);
$scope.cars[index].targaauto = $scope.targaauto;
$scope.cars[index].datiintestatario = $scope.datiintestatario;
$scope.cars[index].marca = $scope.marca;

        $scope.id = " ";
        $scope.targaauto = " ";
        $scope.datiintestatario = " ";
        $scope.marca = " ";
};
});

Answer №1

When dealing with an array like "cars," it is important to understand how to access properties of specific items within the array. To retrieve the "targaauto" property of the first item in the array, you can use the following code:

$scope.cars[0].targaauto  

To determine the length of the "targaauto" property, you would use the following code:

$scope.cars[0].targaauto.length 

Answer №2

Looking at your scenario, it seems like you are inserting data into an array based on $scope variables. The issue lies in attempting to verify the existence of a zero-length plate within the $scope.cars array when the real concern should be focused on the $scope.targaauto variable. To address this, I made a slight modification by incorporating the trim() function to eliminate any potential spaces and included a return alert... statement to prevent incomplete data from being added to the cars array.

$scope.aggiungi = function() {
  if($scope.targaauto.trim().length==0){
    return alert("Error! Please enter the license plate number");
  }
  // .... rest of function

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