I'm writing a little threaded discussion board in angular. I want to use hallo.js for my inline editor (or something similar, the problem doesn't actually depend on hallo).
Here's the relevant snippet from the template
<div ng-show="post.editing" ng-bind-html="post.body" edit-hallo class="col-xs-8"></div>
<div ng-show="!post.editing" ng-bind-html="post.body" class="col-xs-8"></div>
Here's my directive:
Appl.directive('editHallo', function () {
return {
restrict: 'AC',
scope: true,
link: function(scope, element, attr) {
element
.hallo({
plugins: {
'halloformat': {"bold": true, "italic": true, "strikethrough": true, "underline": true},
'halloheadings': [1,2,3],
'hallojustify' : {},
}
});
element.bind('hallomodified', function(event, data) {
scope.post.body = data.content;
});
}
};
});
This all works just fine, but the hack is right there at the end - when there's a hallomodified event, I manually say, scope.post.body = data.content which not only feels like a hack, it means this only works when there's a post.body item that I'm editing, and therefore doesn't work well if I want to repurpose this for the profile editor or whatever.
So my question is: how should I refactor this so that the relevant two-way binding works? I tried a few things that seemed obvious, such as putting a app-model="post.body" in the div, and then doing an isolate scope with =, but that wasn't getting me anywhere. Ideally, I'd pass in the appropriate model using an ng-model directive, but that seems to have changed sometime between when all the directive examples I found online were created and angular 1.2.0.
There's been some time I don't use AngularJS.
But I think the best way would be to change the scope to something like:
scope:{ngModel:'='}
or
scope:{attribute:'='}
That way it should make a two data binding. One with ng-model on first case, or attribute on second.
Then you can just do this when event happens:
scope.$apply(function(){
scope.ngModel=newValue;
})
The apply will be needed so angular can call digest cycle again and update the view.
More info, I think this can help:
http://docs.angularjs.org/guide/directive
Related
I followed this YouTube on Directives
https://www.youtube.com/watch?v=0r5QvzjjKDc
and it was very good, imo. Got through following along successfully right up until the very end (link). The debugger is telling me
TypeError: element.click is not a function
I've looked at this seven ways to Sunday and I'm just not seeing where it's not matching what he's got. Is the syntax error jumping out at you?
Thanks.
angular
.module('app.directives.contactCard', [])
.directive('contactCard', function() {
return {
/* choices are E-Element, A-Attribute, or C */
restrict: 'E',
scope: {
friend: '=',
title: '=',
},
replace: true,
transclude: true,
templateUrl: "contactCard.html",
link: function(scope, element, attrs) {
element.click(function() {
alert('click');
});
},
controller: function($scope) {
console.log($scope.friend);
}
}
})
This looks pretty good, just a slight problem with the element syntax. The error is indicating there is no such function (i.e. click()) on element.
Try using the following, which uses bind:
element.bind('click', function() {
alert('click');
})
I replicated your directive here: http://plnkr.co/edit/SX0zwYipydVvo6EMVfzE
Overall you're on the right track, but the hypothetical click function like that is more reminiscent of the jQuery way of doing things than the Angular way. Typically, if it feels like you're trying to manipulate the features of the DOM through JS, you're thinking in jQuery instead of Angular. I realize that the tutorial utilized it, but it somewhat defeats the purpose of Angular, and I think hides a lot of its real power.
Common conventions for click-functions would be to assign a function to $scope in the directive's controller (or to the directive itself), then refer to it with ng-click in the directive's template.
If you can update your question to include the template, I can give a more specific example. I expect it'll be extremely succinct.
Here is the minimal code to describe the issue. On the page, I have:
<div ng-controller='AController as a'>
<div a-directive></div>
</div>
In js, I have:
app.directive("aDirective", function($compile){
return {
scope: true,
link: function(scope, element, attrs) {
var template = "<h1>{{a.label}}</h1>";
element.append($compile(template)(scope));
}
}
});
app.controller("AController", function($scope){
self = this;
self.label = "some text";
});
That works, but the issue is that {{a.label}}, which made the view and controller/model tightly coupled. Is there any way to get rid of that a., and not to mention the controllerAs-name in the directive code at all? (just like what I did in the controller code)
To improve this you can pass the text to display as a parameter to the directive. Something like this is the initial idea:
<div a-directive="a.label"></div>
However, I DO recommend using an alias for the controller, so I made a Plunker where you can see all of this working together with some improvements.
Check it out here: http://plnkr.co/edit/1hBSBxwSEPXoj9TULzRQ?p=preview
I would also recommend to use template instead of link and restricting the directive to an element instead of using it as attribute, since it is modifying the DOM. But yeah, you could keep improving it till the end of the times :)
What I'm trying to achieve is relatively simple, but I've been going round in circles with this for too long, and now it's time to seek help.
Basically, I have created a directive that is comprised of a text input and a link to clear it.
I pass in the id via an attribute which works in fine, but I cannot seem to work out how to pass the model in to clear it when the reset link is clicked.
Here is what I have so far:
In my view:
<text-input-with-reset input-id="the-relevant-id" input-model="the.relevant.model"/>
My directive:
app.directive('textInputWithReset', function() {
return {
restrict: 'AE',
replace: 'true',
template: '<div class="text-input-with-reset">' +
'<input ng-model="inputModel" id="input-id" type="text" class="form-control">' +
'<a href class="btn-reset"><span aria-hidden="true">×</span></a>' +
'</div>',
link: function(scope, elem, attrs) {
// set ID of input for clickable labels (works)
elem.find('input').attr('id', attrs.inputId);
// Reset model and clear text field (not working)
elem.find('a').bind('click', function() {
scope[attrs.inputModel] = '';
});
}
};
});
I'm obviously missing something fundamental - any help would be greatly appreciated.
You should call scope.$apply() after resetting inputModel in your function where you reset the value.
elem.find('a').bind('click', function() {
scope.inputModel = '';
scope.$apply();
});
Please, read about scope in AngularJS here.
$apply() is used to execute an expression in angular from outside of the angular framework. (For example from browser DOM events, setTimeout, XHR or third party libraries). Because we are calling into the angular framework we need to perform proper scope life cycle of exception handling, executing watches.
I've also added declaring of your inputModel attribute in scope of your directive.
scope: {
inputModel: "="
}
See demo on plunker.
But if you can use ng-click in your template - use it, it's much better.
OK, I seem to have fixed it by making use of the directive scope and using ng-click in the template:
My view:
<text-input-with-reset input-id="the-relevant-id" input-model="the.relevant.model"/>
My directive:
app.directive('textInputWithReset', function() {
return {
restrict: 'AE',
replace: 'true',
scope: {
inputModel: '='
},
template: '<div class="text-input-with-reset">' +
'<input ng-model="inputModel" id="input-id" type="text" class="form-control">' +
'<a href ng-click="inputModel = \'\'" class="btn-reset"><span aria-hidden="true">×</span></a>' +
'</div>',
link: function(scope, elem, attrs) {
elem.find('input').attr('id', attrs.inputId);
};
});
It looks like you've already answered your question, but I'll leave my answer here for further explanations in case someone else lands on the same problem.
In its current state, there are two things wrong with your directive:
The click handler will trigger outside of Angular's digest cycle. Basically, even if you manage to clear the model's value, Angular won't know about it. You can wrap your logic in a scope.$apply() call to fix this, but it's not the correct solution in this case - keep reading.
Accessing the scope via scope[attrs.inputModel] would evaluate to something like scope['the.relevant.model']. Obviously, the name of your model is not literally the.relevant.model, as the dots typically imply nesting instead of being a literal part of the name. You need a different way of referencing the model.
You should use an isolate scope (see here and here) for a directive like this. Basically, you'd modify your directive to look like this:
app.directive('textInputWithReset', function() {
return {
restrict: 'AE',
replace: 'true',
template: [...],
// define an isolate scope for the directive, passing in these scope variables
scope: {
// scope.inputId = input-id attribute on directive
inputId: '=inputId',
// scope.inputModel = input-model attribute on directive
inputModel: '=inputModel'
},
link: function(scope, elem, attrs) {
// set ID of input for clickable labels (works)
elem.find('input').attr('id', scope.inputId);
// Reset model and clear text field (not working)
elem.find('a').bind('click', function() {
scope.inputModel = '';
});
}
};
});
Notice that when you define an isolate scope, the directive gets its own scope with the requested variables. This means that you can simply use scope.inputId and scope.inputModel within the directive, instead of trying to reference them in a roundabout way.
This is untested, but it should pretty much work (you'll need to use the scope.$apply() fix I mentioned before). You might want to test the inputId binding, as you might need to pass it a literal string now (e.g. put 'input-id' in the attribute to specify that it is a literal string, instead of input-id which would imply there is an input-id variable in the scope).
After you get your directive to work, let's try to make it work even more in "the Angular way." Now that you have an isolate scope in your directive, there is no need to implement custom logic in the link function. Whenever your link function has a .click() or a .attr(), there is probably a better way of writing it.
In this case, you can simplify your directive by using more built-in Angular logic instead of manually modifying the DOM in the link() function:
<div class="text-input-with-reset">
<input ng-model="inputModel" id="{{ inputId }}" type="text" class="form-control">
<span aria-hidden="true">×</span>
</div>
Now, all your link() function (or, better yet, your directive's controller) needs to do is define a reset() function on the scope. Everything else will automatically just work!
I am just getting started with angular and ran into the directive below. I read a few tutorials already and am reading some now, but I really don't understand what "require: ngModel" does, mainly because I have no idea what ngModel does overall. Now, if I am not insane, it's the same directive that provides two way binding (the whole $scope.blah = "blah blah" inside ctrl, and then {{blah}} to show 'blah blah' inside an html element controlled by directive.
That doesn't help me here. Furthermore, I don't understand what "model: '#ngModel' does. #ngModel implies a variable on the parents scope, but ngModel isn't a variable there.
tl;dr:
What does "require: ngModel" do?
What does "model : '#ngModel'" do?
*auth is a service that passes profile's dateFormat property (irrelevant to q)
Thanks in advance for any help.
angular.module('app').directive('directiveDate', function($filter, auth) {
return {
require: 'ngModel',
scope: {
model : '#ngModel',
search: '=?search'
},
restrict: 'E',
replace: true,
template: '<span>{{ search }}</span>',
link: function($scope) {
$scope.set = function () {
$scope.text = $filter('date')($scope.model, auth.profile.dateFormat );
$scope.search = $scope.text;
};
$scope.$watch( function(){ return $scope.model; }, function () {
$scope.set();
}, true );
//update if locale changes
$scope.$on('$localeChangeSuccess', function () {
$scope.set();
});
}
};
});
ngModel is an Angular directive responsible for data-binding. Through its controller, ngModelController, it's possible to create directives that render and/or update the model.
Take a look at the following code. It's a very simple numeric up and down control. Its job is to render the model and update it when the user clicks on the + and - buttons.
app.directive('numberInput', function() {
return {
require: 'ngModel',
restrict: 'E',
template: '<span></span><button>+</button><button>-</button>',
link: function(scope, element, attrs, ngModelCtrl) {
var span = element.find('span'),
plusButton = element.find('button').eq(0),
minusButton = element.find('button').eq(1);
ngModelCtrl.$render = function(value) {
updateValue();
};
plusButton.on('click', function() {
ngModelCtrl.$setViewValue(ngModelCtrl.$modelValue + 1);
updateValue();
});
minusButton.on('click', function() {
ngModelCtrl.$setViewValue(ngModelCtrl.$modelValue - 1);
updateValue();
});
function updateValue(value) {
span.html(ngModelCtrl.$modelValue);
}
}
};
});
Working Plunker
Since it interacts with the model, we can use ngModelController. To do that, we use the require option to tell Angular we want it to inject that controller into the link function as its fourth argument. Now, ngModelController has a vast API and I won't get into much detail here. All we need for this example are two methods, $render and $setViewValue, and one property, $modelValue.
$render and $setViewValue are two ways of the same road. $render is called by Angular every time the model changes elsewhere so the directive can (re)render it, and $setViewValue should be called by the directive every time the user does something that should change the model's value. And $modelValue is the current value of the model. The rest of the code is pretty much self-explanatory.
Finally, ngModelController has an arguably shortcoming: it doesn't work well with "reference" types (arrays, objects, etc). So if you have a directive that binds to, say, an array, and that array later changes (for instance, an item is added), Angular won't call $render and the directive won't know it should update the model representation. The same is true if your directive adds/removes an item to/from the array and call $setViewValue: Angular won't update the model because it'll think nothing has changed (although the array's content has changed, its reference remains the same).
This should get you started. I suggest that you read the ngModelController documentation and the official guide on directives so you can understand better how this all works.
P.S: The directive you have posted above isn't using ngModelController at all, so the require: 'ngModel' line is useless. It's simply accessing the ng-model attribute to get its value.
I have this directive
angular.module('xxx', [
])
.directive('qnDropdown', [
'$parse',
function($parse) {
return {
restrict: 'A',
require: 'ngModel',
link: function(scope, elem, attr, ngModel) {
scope.$watch(attr.qnDropdown, function(source) {
var model = $parse(attr.ngModel);
elem.kendoDropDownList({
dataTextField: "Name",
dataValueField: "ID",
value: attr.value,
select: function(e) {
var item = this.dataItem(e.item.index());
scope.$apply(function() {
model.assign(scope, item.value);
});
},
//template: '<strong>${ data.Name }</strong><p>${ data.ID }</p>',
dataSource: source
});
});
}
};
}]);
Input field is
<input qn:dropdown="locations" ng:model="installation.LocationID" value="{{installation.LocationID}}" />
EVerything works fine but initial value for kendoDropDownList is not filled (value: attr.value).
I suppose I am doing something at wrong place or time but not sure what?
You probably need to use $observe:
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 to undefined. -- docs, see section Attributes.
Here's an example where I used $observe recently. See also #asgoth's answer there, where he uses $watch, but he also created an isolate scope.
I'm still not clear on when we need to use $observe vs when we can use $watch.
Are you sure {{installation.LocationID}} has a value you expect? I was able to copy-paste your code with some tweaks for my situation and the dropdownlist is working wonderfully (thank you for doing the hard work for me!). I'm populating value on the input field and when the directive executes, attr.value has it and Kendo shows it as expected. Perhaps this was an Angular issue a couple versions ago?
I had the same problem, the attr.value was empty. The problem was related to an $http async call being made to get the data. The scope data was not yet populated when the dropdownlist was being defined in the directive.
I fixed this by watching attr.ngModel instead of attr.qnDropdown in the link function of the directive. This way the dropdownlist gets defined when the scope data is populated.