AngularJS - Create a directive that uses ng-model
I am trying to create a directive that would create an input field with the same ng-model as the element that creates the directive.
Here's what I came up with so far:
HTML
<!doctype html>
<html ng-app="plunker" >
<head>
<meta charset="utf-8">
<title>AngularJS Plunker</title>
<link rel="stylesheet" href="style.css">
<script>document.write("<base href=\"" + document.location + "\" />");</script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.2/angular.js"></script>
<script src="app.js"></script>
</head>
<body ng-controller="MainCtrl">
This scope value <input ng-model="name">
<my-directive ng-model="name"></my-directive>
</body>
</html>
JavaScript
var app = angular.module('plunker', []);
app.controller('MainCtrl', function($scope) {
$scope.name = "Felipe";
});
app.directive('myDirective', function($compile) {
return {
restrict: 'E',
scope: {
ngModel: '='
},
template: '<div class="some"><label for="{{id}}">{{label}}</label>' +
'<input id="{{id}}" ng-model="value"></div>',
replace: true,
require: 'ngModel',
link: function($scope, elem, attr, ctrl) {
$scope.label = attr.ngModel;
$scope.id = attr.ngModel;
console.debug(attr.ngModel);
console.debug($scope.$parent.$eval(attr.ngModel));
var textField = $('input', elem).
attr('ng-model', attr.ngModel).
val($scope.$parent.$eval(attr.ngModel));
$compile(textField)($scope.$parent);
}
};
});
However, I am not confident this is the right way to handle this scenario, and there is a bug that my control is not getting initialized with the value of the ng-model target field.
Here's a Plunker of the code above: http://plnkr.co/edit/IvrDbJ
What's the correct way of handling this?
EDIT: After removing the ng-model="value"
from the template, this seems to be working fine. However, I will keep this question open because I want to double check this is the right way of doing this.
EDIT: This answer is old and likely out of date. Just a heads up so it doesn't lead folks astray. I no longer use Angular so I'm not in a good position to make improvements.
It's actually pretty good logic but you can simplify things a bit.
Directive
var app = angular.module('plunker', []);
app.controller('MainCtrl', function($scope) {
$scope.model = { name: 'World' };
$scope.name = "Felipe";
});
app.directive('myDirective', function($compile) {
return {
restrict: 'AE', //attribute or element
scope: {
myDirectiveVar: '=',
//bindAttr: '='
},
template: '<div class="some">' +
'<input ng-model="myDirectiveVar"></div>',
replace: true,
//require: 'ngModel',
link: function($scope, elem, attr, ctrl) {
console.debug($scope);
//var textField = $('input', elem).attr('ng-model', 'myDirectiveVar');
// $compile(textField)($scope.$parent);
}
};
});
Html with directive
<body ng-controller="MainCtrl">
This scope value <input ng-model="name">
<my-directive my-directive-var="name"></my-directive>
</body>
CSS
.some {
border: 1px solid #cacaca;
padding: 10px;
}
You can see it in action with this Plunker.
Here's what I see:
- I understand why you want to use 'ng-model' but in your case it's not necessary. ng-model is to link existing html elements with a value in the scope. Since you're creating a directive yourself you're creating a 'new' html element, so you don't need ng-model.
EDIT As mentioned by Mark in his comment, there's no reason that you can't use ng-model, just to keep with convention.
- By explicitly creating a scope in your directive (an 'isolated' scope), the directive's scope cannot access the 'name' variable on the parent scope (which is why, I think, you wanted to use ng-model).
- I removed ngModel from your directive and replaced it with a custom name that you can change to whatever.
- The thing that makes it all still work is that '=' sign in the scope. Checkout the docs docs under the 'scope' header.
In general, your directives should use the isolated scope (which you did correctly) and use the '=' type scope if you want a value in your directive to always map to a value in the parent scope.
I took a combo of all answers, and now have two ways of doing this with the ng-model attribute:
- With a new scope which copies ngModel
- With the same scope which does a compile on link
var app = angular.module('model', []);
app.controller('MainCtrl', function($scope) {
$scope.name = "Felipe";
$scope.label = "The Label";
});
app.directive('myDirectiveWithScope', function() {
return {
restrict: 'E',
scope: {
ngModel: '=',
},
// Notice how label isn't copied
template: '<div class="some"><label>{{label}}: <input ng-model="ngModel"></label></div>',
replace: true
};
});
app.directive('myDirectiveWithChildScope', function($compile) {
return {
restrict: 'E',
scope: true,
// Notice how label is visible in the scope
template: '<div class="some"><label>{{label}}: <input></label></div>',
replace: true,
link: function ($scope, element) {
// element will be the div which gets the ng-model on the original directive
var model = element.attr('ng-model');
$('input',element).attr('ng-model', model);
return $compile(element)($scope);
}
};
});
app.directive('myDirectiveWithoutScope', function($compile) {
return {
restrict: 'E',
template: '<div class="some"><label>{{$parent.label}}: <input></label></div>',
replace: true,
link: function ($scope, element) {
// element will be the div which gets the ng-model on the original directive
var model = element.attr('ng-model');
return $compile($('input',element).attr('ng-model', model))($scope);
}
};
});
app.directive('myReplacedDirectiveIsolate', function($compile) {
return {
restrict: 'E',
scope: {},
template: '<input class="some">',
replace: true
};
});
app.directive('myReplacedDirectiveChild', function($compile) {
return {
restrict: 'E',
scope: true,
template: '<input class="some">',
replace: true
};
});
app.directive('myReplacedDirective', function($compile) {
return {
restrict: 'E',
template: '<input class="some">',
replace: true
};
});
.some {
border: 1px solid #cacaca;
padding: 10px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0/angular.min.js"></script>
<div ng-app="model" ng-controller="MainCtrl">
This scope value <input ng-model="name">, label: "{{label}}"
<ul>
<li>With new isolate scope (label from parent):
<my-directive-with-scope ng-model="name"></my-directive-with-scope>
</li>
<li>With new child scope:
<my-directive-with-child-scope ng-model="name"></my-directive-with-child-scope>
</li>
<li>Same scope:
<my-directive-without-scope ng-model="name"></my-directive-without-scope>
</li>
<li>Replaced element, isolate scope:
<my-replaced-directive-isolate ng-model="name"></my-replaced-directive-isolate>
</li>
<li>Replaced element, child scope:
<my-replaced-directive-child ng-model="name"></my-replaced-directive-child>
</li>
<li>Replaced element, same scope:
<my-replaced-directive ng-model="name"></my-replaced-directive>
</li>
</ul>
<p>Try typing in the child scope ones, they copy the value into the child scope which breaks the link with the parent scope.
<p>Also notice how removing jQuery makes it so only the new-isolate-scope version works.
<p>Finally, note that the replace+isolate scope only works in AngularJS >=1.2.0
</div>
I'm not sure I like the compiling at link time. However, if you're just replacing the element with another you don't need to do that.
All in all I prefer the first one. Simply set scope to {ngModel:"="}
and set ng-model="ngModel"
where you want it in your template.
Update: I inlined the code snippet and updated it for Angular v1.2. Turns out that isolate scope is still best, especially when not using jQuery. So it boils down to:
-
Are you replacing a single element: Just replace it, leave the scope alone, but note that replace is deprecated for v2.0:
app.directive('myReplacedDirective', function($compile) { return { restrict: 'E', template: '<input class="some">', replace: true }; });
-
Otherwise use this:
app.directive('myDirectiveWithScope', function() { return { restrict: 'E', scope: { ngModel: '=', }, template: '<div class="some"><input ng-model="ngModel"></div>' }; });