Cannot inject an Angular ngModel in directive in Kendo Grid - angularjs

Question

I am trying to add an input directive in order to trim all text inputs. So far this is the code of my directive:
app.directive("input", function directive() {
return {
restrict: "E",
priority: 1,
require: "ngModel",
link: function link(scope, element, attrs, ctrl) {
element.on("focusout", function triggerChange(event) {
var input = event.target;
if (input.value && input.type === "text") {
ctrl.$setViewValue(input.value.trim());
ctrl.$render();
}
});
}
};
});
My issue is that the ngModel does not seem to be injected, as I get the error:
Error: [$compile:ctreq] Controller 'ngModel', required by directive 'input', can't be found!
Any idea why this happens, and how to fix it?
Update:
Actually, this is the interaction of Kendo Grid and AngularJS. The input I am testing is generated by Kendo Grid. The code of the column is standard:
{ field: "name", title: "titleName" }

Answer 1

You must have some input element in your HTML which does not have ng-model.
You can change your code to require: "?ngModel", and later check if ctrl is undefined or not, like:
app.directive("input", function directive() {
return {
restrict: "E",
priority: 1,
require: "?ngModel",
link: function link(scope, element, attrs, ctrl) {
if (!ctrl) { return ;}
element.on("focusout", function triggerChange(event) {
var input = event.target;
if (input.value && input.type === "text") {
ctrl.$setViewValue(input.value.trim());
ctrl.$render();
}
});
}
};

Answer 2

You should have provided ng-model in your html when you use this directive because you wrote require: 'ngModel', in the directive. so in your case your directive name is input so it will be something like
<input ng-model="something"> </input>

Answer 3

My answer is not perfect, but it is the best I could find:
app.directive("input", function directive() {
return {
restrict: "E",
priority: 1,
require: "ngModel",
link: function link(scope, element, attrs, ctrl) {
element.on("focusout", function triggerChange(event) {
var input = $(event.target);
input.val(input.val().trim());
input.trigger("change");
});
}
};
});
So basically, we trim the input, and use input.trigger("change") to inform the system that the input has changed.
A warning though, it does not work with our validation system (valdr).