I'm trying to get an evaluated attribute from my custom directive, but I can't find the right way of doing it.
I've created this jsFiddle to elaborate.
<div ng-controller="MyCtrl">
<input my-directive value="123">
<input my-directive value="{{1+1}}">
</div>
myApp.directive('myDirective', function () {
return function (scope, element, attr) {
element.val("value = "+attr.value);
}
});
What am I missing?
This question is related to
javascript
binding
angularjs
directive
var myApp = angular.module('myApp',[]);
myApp .directive('myDirective', function ($timeout) {
return function (scope, element, attr) {
$timeout(function(){
element.val("value = "+attr.value);
});
}
});
function MyCtrl($scope) {
}
Use $timeout because directive call after dom load so your changes doesn`'t apply
For an attribute value that needs to be interpolated in a directive that is not using an isolated scope, e.g.,
<input my-directive value="{{1+1}}">
use Attributes' method $observe
:
myApp.directive('myDirective', function () {
return function (scope, element, attr) {
attr.$observe('value', function(actual_value) {
element.val("value = "+ actual_value);
})
}
});
From the directive page,
observing interpolated attributes: Use
$observe
to observe the value changes of attributes that contain interpolation (e.g.src="{{bar}}"
). Not only is this very efficient but it's also the only way to easily get the actual value because during the linking phase the interpolation hasn't been evaluated yet and so the value is at this time set toundefined
.
If the attribute value is just a constant, e.g.,
<input my-directive value="123">
you can use $eval if the value is a number or boolean, and you want the correct type:
return function (scope, element, attr) {
var number = scope.$eval(attr.value);
console.log(number, number + 1);
});
If the attribute value is a string constant, or you want the value to be string type in your directive, you can access it directly:
return function (scope, element, attr) {
var str = attr.value;
console.log(str, str + " more");
});
In your case, however, since you want to support interpolated values and constants, use $observe
.
The other answers here are very much correct, and valuable. But sometimes you just want simple: to get a plain old parsed value at directive instantiation, without needing updates, and without messing with isolate scope. For instance, it can be handy to provide a declarative payload into your directive as an array or hash-object in the form:
my-directive-name="['string1', 'string2']"
In that case, you can cut to the chase and just use a nice basic angular.$eval(attr.attrName)
.
element.val("value = "+angular.$eval(attr.value));
Working Fiddle.
For the same solution I was looking for Angularjs directive with ng-Model
.
Here is the code that resolve the problem.
myApp.directive('zipcodeformatter', function () {
return {
restrict: 'A', // only activate on element attribute
require: '?ngModel', // get a hold of NgModelController
link: function (scope, element, attrs, ngModel) {
scope.$watch(attrs.ngModel, function (v) {
if (v) {
console.log('value changed, new value is: ' + v + ' ' + v.length);
if (v.length > 5) {
var newzip = v.replace("-", '');
var str = newzip.substring(0, 5) + '-' + newzip.substring(5, newzip.length);
element.val(str);
} else {
element.val(v);
}
}
});
}
};
});
HTML DOM
<input maxlength="10" zipcodeformatter onkeypress="return isNumberKey(event)" placeholder="Zipcode" type="text" ng-readonly="!checked" name="zipcode" id="postal_code" class="form-control input-sm" ng-model="patient.shippingZipcode" required ng-required="true">
My Result is:
92108-2223
Source: Stackoverflow.com