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amp-list

Description Fetches content dynamically from a CORS JSON endpoint and renders it using a supplied template.
Availability Stable
Required Script <script async custom-element="amp-list" src="https://cdn.ampproject.org/v0/amp-list-0.1.js"></script>
Supported Layouts fill, fixed, fixed-height, flex-item, nodisplay, responsive
Examples Annotated code example for amp-list

Usage

The amp-list defines data source using the following attributes:

  • src defines a CORS URL. The URL's protocol must be HTTPS.
  • credentials defines a credentials option as specified by the Fetch API. To send credentials, pass the value of "include". If this is set, the response must follow the AMP CORS security guidelines.

The response is expected to contain the array that will be rendered. The path to the array is specified using the optional items attribute. This attribute contains the dot-notated path to the array within the response object. The default value is "items". To indicate that the response itself is an array, the "." value can be used. The array can be nested within the response and accessed using, e.g. items="field1.field2" expression.

Thus, when items="items" is specified (the default) the response must be a JSON object that contains an array property "items":

{
  "items": [...]
}

The template can be specified using either of the following two ways:

  • template attribute that references an ID of an existing template element.
  • template element nested directly inside of this amp-list element.

For more details on templates, see AMP HTML Templates.

Optionally, amp-list element can contain an element with overflow attribute. This element will be shown if AMP Runtime cannot resize the amp-list element as requested.

Example: Using overflow

<amp-list src="https://data.com/articles.json?ref=CANONICAL_URL"
    width=300 height=200 layout=responsive>
  <template type="amp-mustache">
    <div>
      <amp-img src="{{imageUrl}}" width=50 height=50></amp-img>
      {{title}}
    </div>
  </template>
  <div overflow role=button aria-label="Show more" class="list-overflow">
    Show more
  </div>
</amp-list>
.list-overflow {
  position: absolute;
  bottom: 0;
}

Substitutions

The amp-list allows all standard URL variable substitutions. See Substitutions Guide for more info.

For example:

<amp-list src="https://foo.com/list.json?RANDOM"></amp-list>

may make a request to something like https://foo.com/list.json?0.8390278471201 where the RANDOM value is randomly generated upon each impression.

Behavior

The request is always made from the client, even if the document was served from the AMP cache. Loading is triggered using normal AMP rules depending on how far the element is from the current viewport.

If amp-list needs more space after loading it requests the AMP runtime to update its height using the normal AMP flow. If AMP Runtime cannot satisfy the request for new height, it will display overflow element when available. Notice however, the typical placement of amp-list elements at the bottom of the document almost always guarantees that AMP Runtime can resize it.

By default, amp-list adds list ARIA role to the list element and listitem role to item elements rendered via the template.

Attributes

src (required)

The URL location of the remote endpoint that will return the JSON that will be rendered within this amp-list. This must be a CORS HTTP service.

credentials (optional)

Defines a credentials option as specified by the Fetch API. To send credentials, pass the value of "include". If this is set, the response must follow the AMP CORS security guidelines.

The support values are "omit" and "include". Default is "omit".

items

Defines the expression to locate the array to be rendered within the response. It's a dot-notated expression that navigates via fields of the JSON response. Notice:

  • The default value is "items". The expected response: {items: [...]}.
  • If the response itself is the desired array, use the value of ".". The expected response is: [...].
  • Nest navigation is permitted (e.g., "field1.field2"). The expected response is: {field1: {field2: [...]}}.

common attributes

This element includes common attributes extended to AMP components.

Validation

See amp-list rules in the AMP validator specification.