Angular 1.5 Component: passing a function

Question

Is it possible to passing a function to a component and call this function inside the component passing a parameter?

Example:

List of posts

<post-list posts="blog.posts"
           loading="blog.loadingPosts"
           get-post-url="blog.getPostUrl" 
           is-user-authenticate="blog.user">
</post-list>

getPostUrl is a function (inside the container controller):

const getPostUrl = (postId) => {
    const protocol = $location.protocol();
    const host = $location.host();
    const port = $location.port();

    return protocol + "://" + host + "" + (port !== 80 ? ":" + port : "") + "/blog/post/" + postId;
};

List of posts: component

const PostList = {
  "bindings": {
    "posts": "<",
    "loading": "<",
    "getPostUrl": "&", //Function getPostUrl
    "isUserAuthenticate": "<"
  },
  "template": `<div>
                <div class="col-md-9 text-center" data-ng-if="$ctrl.loading">
                  <i class="fa fa-spinner fa-spin fa-2x"></i>
                </div>

                <div class="col-md-9 posts" data-ng-if="!$ctrl.loading">
                  <div data-ng-repeat="post in $ctrl.posts">
                    <post creation-date="{{post.creationDate}}"
                          content="{{post.content}}"
                          post-url="{{$ctrl.getPostUrl(post.creationDate)}}"
                          is-user-authenticate="$ctrl.user">
                    </post>
                  </div>
                </div>
              </div>`,
   "transclude": false
};

 angular
  .module("blog")
  .component("postList", PostList);

In this line:

post-url="{{$ctrl.getPostUrl(post.creationDate)}}" I want to call the function passing a parameter and this function is returning a string.

In post component (not PostList) the postUrl is a string attribute @.

But... Is not working!

angular.js:13550 Error: [$interpolate:interr] Can't interpolate: {{$ctrl.getPostUrl(post.creationDate)}} TypeError: Cannot use 'in' operator to search for 'blog' in 1459329888892 Error Link

Is it possible to do it? And how?

Thank you so much!

Answer 1

If you want to call the function from inside a component and have it return a value then you need two-way binding:

"bindings": {
  "posts": "<",
  "loading": "<",
  "getPostUrl": "=", // <-- two-way binding
  "isUserAuthenticate": "<"
},

However, this is probably not very good idea. Consider passing data to component rather than making component request data from outside. This will make much better isolated component.

Answer 2

You can pass functions to components, but you must define the function arguments as object with the correct arguments names as its keys. example:

<post-list posts="blog.posts"
           loading="blog.loadingPosts"
           get-post-url="blog.getPostUrl(postId)" 
           is-user-authenticate="blog.user">
</post-list>

const PostList = {
 "bindings": {
  "posts": "<",
  "loading": "<",
  "getPostUrl": "&", //Function getPostUrl
  "isUserAuthenticate": "<"
 },
 "template": `<post creation-date="{{post.creationDate}}"
                      content="{{post.content}}"
                      post-url="{{$ctrl.getPostUrl({postId:post.creationDate})}}">
                </post>