So I need to be able to call a function of a directives controller, have it wrap an existing child directive in a new one while maintaining the now wrapped directive's state (both it's controller and all possible children) and otherwise modify the parent directive's template. This process also has to able to reversed.
Quick and super dirty fiddle to show the idea
So the DOM starts as:
<split>
<innerDirective></innerDirective>
</split>
When the split directive's controller's function is called, this should happen:
<split> // same outer parent
<split> // new directive
<innerDirective></innerDirective>// SAME innerDirective instance
</split>
<split>// new directive
<innerDirective></innerDirective> //New innderDirective instance
</split>
</split>
I originally used the .html function to set the split directives content, and used $compile service to reconstruct the DOM. This of course destroys the original innerDirective. Since it may be deep, it is not feasible to store it's data in the parent split and retrieve with a link function (although I tried).
I also tried using jquery's .wrap and .unwrap functions, which works, except the added tags aren't compiled as directives, so not really.
Is there a proper way to do this, or a way to compile just the outer tag added with the .wrap, and update the scope of the innerDirective to the new parent?
Thanks for any help and advice you may have!
Edit:
I have a controller along this lies, lets say set to control the split 'E' directive:
function SplitCtrl($scope, $compile){
//stuff
//First way, redefine html contents and recompile
this.split1 = function(){
//element has been linked to the directive's element
$scope.element.html('<split></split><split></split>');
$compile($scope.element.contents())($scope);
};
//Second way, jquery.wrap
this.split2 = function(){
$($scope.element).children('innerDirective').wrap('<split />');
// then I need to instantiate the new split
// without reinstantiating now wrapped directive.
// Adding second split is fine in this case, I can do that.
};
};
The template is:
<innderDirective></innerDirective>
Related
I'm wondering if there is any way I can get the original {{expression}} after angular has complied the directives and interpolated the expressions. For instance if there is a text e.g. Hi, Filip and the user clicks on it, I want to be able to show a pop-up with Hi, {{name}}.
Now, one way I thought of doing that is by analysing the DOM before angular (e.g. during run) and then saving the expressions as additional attributes to the parent element. However, I run into various problems with that (e.g. if parent has other child elements and they are removed, e.g. with ng-if, then I can't reliably know which expression belongs to which text node).
Since Angular keeps watchers for these expressions, it must have a reference to the text nodes they are applied on. Is there any way I could access those?
The second question is, can I somehow get the original element of ng-repeat (before it was compiled and transcluded), for the similar purpose (allowing the user to modify it on-the-fly).
I want to avoid introducing new directives as this is meant to work on existing angular applications.
I'm not concerned about performance or security (i.e. this is not for production applications but rather for prototyping/debugging).
Use factories to supply to your html expressions with reusable logic. Assumes you're using controller as syntax so you can the controller's scope as this in your view.
// factory
function() {
return 'bob';
}];
// in your controller
['somefactory', function(factory) {
this.factoryString = factory.toString(); // => "function() { return 'bob'; }"
this.factory = factory;
}];
// view
<div>hi {{this.factory()}} you were made with {{this.factoryString}}</div>
// interpolated
<div>hi bob, you were made with function() { return 'bob' }</div>
I didn't test any of that though.
Let's say I'm creating a dynamic directive in angularjs. I want to use the link function to manipulate the DOM of the template html based on the arguments.
So in vanilla javascript, I would do something like the following:
var template = ... //something here that sets the variable to the template
var newdiv = document.createElement("div");
template.appendChild(newdiv);
I found some answers where they treat the template like a string and just splice in the literal string "<div></div>".
However, I plan to do a lot of modification so treating it as a string will quickly get too confusing, and will be unmaintainable if I do it. If possible, I would like to treat it the same way I treat the page's DOM in regular js.
I am also open to having no template, and just dynamically generating the whole thing in the link function, if it's possible for me to somehow get the directive to return this
Compiled element can be modified in link function. No bindings or directives can be added to the element at this point without recompilation.
...
link: function (scope, element, attrs) {
// jqLite element that partly implements jQuery API
element.append(...);
// native element that is wrapped with jqLite
var nativeElement = element[0];
nativeElement.appendChild(...);
}
According to the documentation a template can be a function which takes two parameters, an element and attributes and returns a string value representing the template. It replaces the current element with the contents of the HTML. The replacement process migrates all of the attributes and classes from the old element to the new one.
The compile function deals with transforming the template DOM. It takes three parameters, an element, attributes and transclude function. The transclude parameter has been deprecated. It returns a link function.
It appears that a template and a compile functions are very similar and can achieve the same goal. The template function defines a template and compile function modifies the template DOM. However, it can be done in the template function itself. I can't see why modify the template DOM outside the template function. And vice-versa if the DOM can be modified in the compile function then what's the need for a template function?
The compilation function can be used to change the DOM before the resulting template function is bound to the scope.
Consider the following example:
<div my-directive></div>
You can use the compile function to change the template DOM like this:
app.directive('myDirective', function(){
return {
// Compile function acts on template DOM
// This happens before it is bound to the scope, so that is why no scope
// is injected
compile: function(tElem, tAttrs){
// This will change the markup before it is passed to the link function
// and the "another-directive" directive will also be processed by Angular
tElem.append('<div another-directive></div>');
// Link function acts on instance, not on template and is passed the scope
// to generate a dynamic view
return function(scope, iElem, iAttrs){
// When trying to add the same markup here, Angular will no longer
// process the "another-directive" directive since the compilation is
// already done and we're merely linking with the scope here
iElem.append('<div another-directive></div>');
}
}
}
});
So you can use the compile function to change the template DOM to whatever you like if your directive requires it.
In most cases tElem and iElem will be the same DOM element, but sometimes it can be different if a directive clones the template to stamp out multiple copies (cf. ngRepeat).
Behind the scenes, Angular uses a 2-way rendering process (compile + link) to stamp out copies of a compiled piece of DOM, to prevent Angular from having to process (= parse directives) the same DOM over and over again for each instance in case the directive stamps out multiple clones resulting in much better performance.
Hope that helps!
ADDED AFTER COMMENT:
The difference between a template and compile function:
Template function
{
template: function(tElem, tAttrs){
// Generate string content that will be used by the template
// function to replace the innerHTML with or replace the
// complete markup with in case of 'replace:true'
return 'string to use as template';
}
}
Compile function
{
compile: function(tElem, tAttrs){
// Manipulate DOM of the element yourself
// and return linking function
return linkFn(){};
}
}
The template function is called before the compile function is called.
Although they can perform almost identical stuff and share the same 'signature', the key difference is that the return value of the template function will replace the content of the directive (or the complete directive markup if replace: true), while a compile function is expected to change the DOM programmatically and return a link function (or object with pre and post link function).
In that sense you can think of the template function as some kind of convenience function for not having to use the compile function if you simply need to replace the content with a string value.
Hope that helps!
One of the best uses of the template function is to conditionally generate a template. This allows you to automate the creation of a template based on an attribute or any other condition.
I have seen some very large templates that use ng-if to hide sections of the template. But instead of placing everything into the template and using ng-if, which can cause excessive binding, you can remove sections of the DOM from the output of the template function that will never be used.
Let's say you have a directive that will include either sub-directive item-first or item-second. And the sub-directive will not ever change for the life of the outer directive. You can adjust the output of the template, prior to the compile function being called.
<my-item data-type="first"></my-item>
<my-item data-type="second"></my-item>
And the template string for these would be:
<div>
<item-first></item-first>
</div>
and
<div>
<item-second></item-second>
</div>
I agree that this is an extreme simplification, But I have some very complicated directives and the outer directive needs to display one of, about, 20 different inner directives based on a type. Instead of using transclude, I can set the type on the outer directive and have the template function generate the correct template with the correct inner directive.
That correctly formatted template string is then passed on to the compile function, etc.
I have a problem when creating multiple directives with isolated scope: when I change something in 1st directive it also makes changes in all other directives.
Here is a working example: http://plnkr.co/edit/drBghqHHx2qz20fT91mi?p=preview
(try to add more of Type1 'Available notifications' - a change in 1st will reflect in all other directives of Type1)
I found some solutions to similar problems here but they don't work in my case. Also found a working solution with mapping 'subscription' data to local scope variables in directive (app.js, line 76) but I think there should be a more general way to do this right?
In your directive 'notificationitem' you have the following code, keep it in mind as i explan:
// if all variables are mapped in this way than works
//$scope.enabled = $scope.subscription.enabled;
The reason why all of the 'isolated' scopes are updating is because of this code in your scope declaration in the same directive (notificationitem):
scope: {
subscription: '=',
index: '#'
},
The equal sign on subscription is angular's way of saying "Whenever the current scope updates, go to the parent and update that value as well." This means whenever you update your 'isolated' scope, it updates the parent scope as well. Since all of these isolated scopes are binding to the parent, they will change as well.
Since you want the subscription.value to be the default value of that text field, you will need to do exactly what your commented code is doing:
scope.value = scope.subscription.value;
This will create an isolated value inside of the isolated scope. When scope.value changes, scope.subscription.value will not. All of the text fields now have their own 'value' to keep track of.
Check out this article for information on directive bindings: http://www.ng-newsletter.com/posts/directives.html
Also, another way to get the default value would be to inject your service into the directive, if you don't like the above solution. Hope this all helps.
I have a form controller with 2 object models model1:{name:"foo"} model2:{name:"model2"}
I created 2 directives (both which create isolated scopes) . One with Element only binding which uses model1 and another one with Attribute only binding which uses model2.
The nesting is like so:
<div myattibute="model2">
<mytag my-model="model"></mytag>
</div>
The attribute only directive doesn't have a template and the tag directive has a template.
The problem is that I am getting undefined in mytag directive for the model.
1.Can someone see the problem and explain it in the plnkr ?
http://plnkr.co/edit/Q23XqY?p=preview
Partial Solution:
A working example with adding an empty div template with just ng-transclude for the myattribute directive makes it work. With i mandated that this attribute directive is on a div it that I would have wanted it to be placeable on any div, span etc.
Here is the working example:
http://plnkr.co/edit/z0M5ys?p=preview
2.How is ng-transclude affecting scope inheritance?
3.Can't I create this attribute with only business logic without any markup ?
Isolate scopes are best avoided except for rare cases they add unnecessary complexity. It is much simpler to just use $scope.$watch to bind to expressions in attributes like this:
$scope.$watch(attrs.myModel, function(newValue, oldValue) {})
$scope.$watch(attrs.myattribute, function(newValue, oldValue) {})
This way your directives can either share the parent scope they were declared in and handle binding to it using $watch expressions, or they can create a child scope using { scope: true } if needed.
Here is one possible solution: http://plnkr.co/edit/mm2q67?p=preview
Keep in mind that your myTag directive can use an isolate scope if you'd really like to do it that way, but the myattribute one can't as that will break the scope inheritance chain for myTag