amp-autocomplete

Usage

The amp-autocomplete extension should be used for suggesting completed items based on user input to help users carry out their task more quickly.

This can be used to power search experiences, in cases where the user may not know the full range of potential inputs, or in forms to help ensure inputs where there may be multiple ways to express the same intent (using a state abbreviation instead of its full name, for example) yield more predictable results.

Example:

<amp-autocomplete filter="substring" id="myAutocomplete">
  <input />
  <script type="application/json">
    {"items": ["a", "b", "c"]}
  </script>
</amp-autocomplete>

When using the src attribute with amp-autocomplete, the response from the endpoint contains data to be rendered in the specified template.

You can specify a template in one of two ways:

• a template attribute that references an ID of an existing templating element.
• a templating element nested directly inside the amp-autocomplete element.

For more details on templates, see AMP HTML Templates.

<template type="amp-mustache">

  <!-- NOT RECOMMENDED -->
  <div class="item">{{item}}</div>
  <div class="price">{{price}}</div>
</template>

<template type="amp-mustache">

  <!-- RECOMMENDED -->
  <div data-value="{{items}}">
    <div class="item">{{item}}</div>
    <div class="price">{{price}}</div>
  </div>
</template>

Attributes

filter (required)

The filtering mechanism applied to source data to produce filtered results for user input. In all cases the filtered results will be displayed in array order of data retrieved. If filtering is being done (filter != none), it is done client side. The following are supported values:

• substring: if the user input is a substring of an item, then the item is suggested
• prefix: if the user input is a prefix of an item, then the item gets suggested
• token-prefix: if the user input is a prefix of any word in a multi-worded item, then the item gets suggested; example “je” is a token-prefix in “blue jeans”
• fuzzy: typos in the input field can result in partial match items appearing in the filtered results—need further research
• none: no client-side filter; renders retrieved data based on bound [src] attribute; truncates to max-items attribute if provided
• custom: a conditional statement involving an item and a user input to be applied to each item such that evaluating to true implies the item gets suggested; using this filter requires including amp-bind if filter==custom, an additional attribute filter-expr is required to specify a boolean expression by which to perform the custom filter

filter-expr

Required if filter==custom

filter-value

If data is an array of JsonObjects, the filter-value is the property name that will be accessed for client side filtering. This attribute is unnecessary if filter is none. Defaults to "value".

src

The URL of the remote endpoint that returns the JSON that will be filtered and rendered within this amp-autocomplete. This must be a CORS HTTP service and the URL's protocol must be HTTPS. The endpoint must implement the requirements specified in the CORS Requests in AMP spec. If fetching the data at the src URL fails, the amp-autocomplete triggers a fallback. The src attribute may be omitted if the [src] attribute exists.

query

The query parameter to generate a static remote endpoint that returns the JSON that will be filtered and rendered within this amp-autocomplete. This requires the presence of the src attribute. For example, if src="http://www.example.com" and query="q", then when a user types in abc, the component will retrieve data from http://www.example.com?q=abc.

min-characters

The min character length of a user input to provide results, default 1

max-items

The max specified number of items to suggest at once based on a user input, displays all if unspecified

suggest-first

Suggest the first entry in the list of results by marking it active; only possible if filter==prefix (does nothing otherwise)

submit-on-enter

The enter key is primarily used for selecting suggestions in autocomplete, so it shouldn’t also submit the form unless the developer explicitly sets it to do so (for search fields/one field forms, et cetera).

The user flow is as follows: If submit-on-enter is true, pressing Enter will select any currently active item and engage in default behavior, including submitting the form if applicable. If submit-on-enter is false, pressing Enter while suggestions are displaying will select any currently active item only and prevent any other default behavior. If suggestions are not displaying, autocomplete allows default behavior. Defaults to false.

highlight-user-entry

If present, exposes the autocomplete-partial class on the substring within the suggested item that resulted in its match with the user input. This can be used to stylize the corresponding match to stand out to the user. Defaults to false.

items

Specifies the key to the data array within the JSON response. Nested keys can be expressed with a dot-notated value such as field1.field2. The default value is "items". The following are examples with and without usage:

  <amp-autocomplete filter="prefix">
      <input type="text">
      <script type=application/json>
        { "items" : ["apples", "bananas", "pears"] }
       </script>

  </amp-autocomplete>

  <amp-autocomplete filter="prefix" items="fruit">
    <input type="text">
    <script type=application/json>
      { "fruit" : ["apples", "bananas", "pears"] }
      </script>
  </amp-autocomplete>

inline

Whether the amp-autocomplete should autosuggest on the full user input or only a triggered substring of the user input. By default when the attribute is absent, suggestions will be based on the full user input. The attribute cannot have an empty value but must take a single character token, i.e. @ which activates the autocomplete behavior. For example, if inline="@" then user input of hello will not retrieve suggestions but a user input of hello @abc might trigger options filtered on the substring abc. Currently triggered substrings are delimited on whitespace characters, however this is subject to change in the future.

Events

select

amp-autocomplete triggers the select event when the user selects an option via click, tap, keyboard navigation or accepting typeahead. It also fires the select event if a user keyboard navigates to an item and Tabs away from the input field. event contains the value attribute value of the selected element which is its textual representation (e.g., value of data-value).

event may also contain the entire object in the valueAsObject field, if the suggestion template contains data-json={{objToJson}}. This causes the rendered element to have a data-json data attribute with a JSON string representation of the corresponding object, which is then made available in the valueAsObject field of the event.

Example:

<amp-autocomplete
  filter="substring"
  id="myAutocomplete"
  on="select:AMP.setState({chosenFruit: event.valueAsObject})"
>
  <input />
  <script type="application/json">
    {
      "items": [
        {"fruit": "apple", "color": "red"},
        {"fruit": "banana", "color": "yellow"}
      ]
    }
  </script>
  <template type="amp-mustache">
    <div data-value="{{fruit}}" data-json="{{objToJson}}">
{{color}} {{fruit}}    </div>
  </template>
</amp-autocomplete>
<p [text]="'Your fruit: ' + chosenFruit.color + ', ' + chosenFruit.fruit">
  No fruit selected
</p>

Validation

See amp-autocomplete rules in the AMP validator specification.