What is the best way to conditionally apply attributes in AngularJS?

Question

I need to be able to add for example "contenteditable" to elements, based on a boolean variable on scope.

Example use:

<h1 attrs="{'contenteditable=\"true\"': editMode}">{{content.title}}</h1> 

Would result in contenteditable=true being added to the element if $scope.editMode was set to true. Is there some easy way to implement this ng-class like attribute behavior? I'm considering writing a directive and sharing if not.

Edit: I can see that there seems to be some similarities between my proposed attrs directive and ng-bind-attrs, but it was removed in 1.0.0.rc3, why so?

Answer 1

I am using the following to conditionally set the class attr when ng-class can't be used (for example when styling SVG):

ng-attr-class="{{someBoolean && 'class-when-true' || 'class-when-false' }}" 

The same approach should work for other attribute types.

(I think you need to be on latest unstable Angular to use ng-attr-, I'm currently on 1.1.4)

Answer 2

You can prefix attributes with ng-attr to eval an Angular expression. When the result of the expressions undefined this removes the value from the attribute.

<a ng-attr-href="{{value || undefined}}">Hello World</a> 

Will produce (when value is false)

<a ng-attr-href="{{value || undefined}}" href>Hello World</a> 

So don't use false because that will produce the word "false" as the value.

<a ng-attr-href="{{value || false}}" href="false">Hello World</a> 

When using this trick in a directive. The attributes for the directive will be false if they are missing a value.

For example, the above would be false.

function post($scope, $el, $attr) {       var url = $attr['href'] || false;       alert(url === false); }