Check if value is not empty and not null in angular template?

问题

How do I check if value is not empty and not null.

in Controller: $scope.data.variable = 'some valid data';

<div ng-if="data.variable != ''">something else</div>

Thanks

回答1:

since both null and empty are falsy values

div.variable if not null or empty will evaluate to true and if either of null or empty will evaluate to false

 <div ng-if="data.variable">something else</div>

回答2:

I suggest you have such a function is your controller:

$scope.isEmpty = function(value){
return (value == "" || value == null);
};

And your HTML:

<div ng-if="!isEmpty(data.variable)">something else</div>

If this function will be useful in many of your pages I suggest you put it on the $rootScope, so that it's recognized in the entire application.

回答3:

From what it looks like in your case, I think you're expecting either an empty string, or null. To write a reasonable check, I would consider it best to go about it like this;

$scope.isValid = function(val) {
    var ret = true;
    if (angular.isString(val)) {
        ret = ret && (val.length > 0);
    }
    return ret && (val !== null);
}

来源：https://stackoverflow.com/questions/27634736/check-if-value-is-not-empty-and-not-null-in-angular-template