ember

A Sprinkling of Ember

Mar 6, 2014 · Jeffrey Biles

Ember isn’t just for huge ambitious single-page web applications. It’s actually really easy to sprinkle over your static or server-side-rendered web page to add just a little bit of functionality.

You can even use it in a blog. A blog like this one.

Here is a text box. I want you to stick the url for your favorite gif in the text box (or click one of the items below).

This will be replaced with the Ember component!

Notice how the GIF displays automatically when you input the url? Notice how putting in a new GIF automatically adds it to the list?

That’s Ember. In a statically rendered blog (middleman-blog, for the curious).

The following steps are necessary for sprinkling in Ember:

  1. Create a placeholder div for your component
  2. Link to source files for Ember, Handlebars, jQuery
  3. Create an Ember component
  4. Make sure you specify the layoutName to match the data-template-name of your handlebars template
  5. Use jQuery to replace your html div with your Ember component.

Here’s the code for this component (but simplified, without code for the awesome list):

//excuse the not-quite-correct comment structure, html comments didn't appear
//1: create a placeholder div for your component
<div class="component-placeholder">
  Your Ember Component will go here
</div>

//2: Link to source files
<script type="text/javascript" src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript" src="http://builds.handlebarsjs.com.s3.amazonaws.com/handlebars-v1.1.2.js"></script>
<script type="text/javascript" src="http://builds.emberjs.com/tags/v1.4.0/ember.min.js"></script>

//3: Create an Ember Component
<script type="text/x-handlebars" data-template-name="components/fs-gif-url-input">
  <div class="field">
    <label for="gif_link_url">Url</label><br>
    {{input value=gifUrl name="gif_link[url]"}}
  </div>

  <div class="image-preview">
    {{#if urlIsValid}}
      <img {{bind-attr src="gifUrl"}} height=500>
    {{else}}
      <h1>That URL is not valid!</h1>
    {{/if}}
  </div>
</script>

<script type="text/javascript">
  App = Ember.Application.create()
  App.FsGifUrlInputComponent = Ember.Component.extend({
    //4: matching layout name
    layoutName: "components/fs-gif-url-input",
    gifUrl: null,

    urlIsValid: function(){
      if(!!this.get("gifUrl")) {
        return this.get("gifUrl").match(/^(ht|f)tps?:\/\/[a-z0-9-\.]+\.[a-z]{2,4}\/?([^\s<>\#%"\,\{\}\\|\\\^\[\]`]+)?$/);
      }
    }.property("gifUrl")
  });

  //5. Use jQuery to replace your html div with your Ember component.
  $(document).ready(function(){
    // Find the container div.
    $(".component-placeholder").each(function(){
      // Get the existing input value
      var value = $(this).find("input").val()
      // Build the component & stuff in any pre-existing value
      var component = App.FsGifUrlInputComponent.create({
        gifUrl: value
      });
      // Gut out the container div & replace with the component
      component.replaceIn(this);
    });
  });
</script>

Voila! EMBER MAGIC!!!