Aurelia autocomplete

app.html

<template>
  <require from="./autocomplete"></require>
  <form>
    <label class="form-component">
      Country
      <autocomplete service.bind="countryNameService" 
                    value.bind="countryName"
                    placeholder="Country">
      </autocomplete>
    </label>
    
    <label class="form-component">
      Country 2
      <autocomplete service.bind="countryService" 
                    value.bind="country"
                    placeholder="Country">
        <template replace-part="suggestion">
          ${suggestion.code}: ${suggestion.name}
        </template>
      </autocomplete>
    </label>
  </form>
</template>

app.js

import {countries} from './countries';

export class App {
  countryNameService = new CountryNameSuggestionService();
  countryName = null;
  
  countryService = new CountrySuggestionService();
  country = null;
}

export class CountryNameSuggestionService {
  suggest(value) {
    if (value === '') {
      return Promise.resolve([]);
    }
    value = value.toLowerCase();
    const suggestions = countries.filter(x => x.name.toLowerCase().indexOf(value) === 0)
      .map(x => x.name);
    return Promise.resolve(suggestions);
  }
  
  getName(suggestion) {
    return suggestion;
  }
}

export class CountrySuggestionService {
  suggest(value) {
    if (value === '') {
      return Promise.resolve([]);
    }
    value = value.toLowerCase();
    const suggestions = countries.filter(x => x.name.toLowerCase().indexOf(value) === 0);
    return Promise.resolve(suggestions);
  }
  
  getName(suggestion) {
    return suggestion.name;
  }
}

autocomplete.css

autocomplete {
  display: inline-block;
}

autocomplete .suggestions {
  list-style-type: none;
  cursor: default;
  padding: 0;
  margin: 0;
  border: 1px solid #ccc;
  background: #fff;
  box-shadow: -1px 1px 3px rgba(0,0,0,.1);
  
  position: absolute;
  z-index: 9999; 
  max-height: 15rem; 
  overflow: hidden; 
  overflow-y: auto; 
  box-sizing: border-box;
}

autocomplete .suggestion {
  padding: 0 .3rem;
  line-height: 1.5rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: #333;
}

autocomplete .suggestion:hover,
autocomplete .suggestion.selected { 
  background: #f0f0f0;
}

autocomplete.html

<template>
  <require from="./autocomplete.css"></require>

  <input type="text" autocomplete="off"
         aria-autocomplete="list"
         aria-expanded.bind="expanded"
         aria-owns.one-time="'au-autocomplate-' + id + '-suggestions'"
         aria-activedescendant.bind="index >= 0 ? 'au-autocomplate-' + id + '-suggestion-' + index : ''"
         id.one-time="'au-autocomplete-' + id"
         placeholder.bind="placeholder"
         value.bind="inputValue & debounce:delay"
         keydown.delegate="keydown($event.which)"
         blur.trigger="blur()">
  <ul class="suggestions" role="listbox"
      if.bind="expanded"
      id.one-time="'au-autocomplate-' + id + '-suggestions'"
      ref="suggestionsUL">
    <li repeat.for="suggestion of suggestions" 
        id.one-time="'au-autocomplate-' + id + '-suggestion-' + $index"
        role="option"
        class-name.bind="($index === index ? 'selected' : '') + ' suggestion'"
        mousedown.delegate="suggestionClicked(suggestion)">
      <template replaceable part="suggestion">
        ${suggestion}
      </template>
    </li>
  </ul>
</template>

autocomplete.js

import {bindingMode, observable} from 'aurelia-binding';
import {bindable} from 'aurelia-templating';
import {inject} from 'aurelia-dependency-injection';
import {DOM} from 'aurelia-pal';

let nextID = 0;

@inject(Element)
export class Autocomplete {
  @bindable service;
  @bindable({ defaultBindingMode: bindingMode.twoWay }) value;
  @bindable placeholder = '';
  @bindable delay = 300;
  id = nextID++;
  expanded = false;
  @observable inputValue = '';
  updatingInput = false;
  suggestions = [];
  index = -1;
  suggestionsUL = null;
  userInput = '';
  
  constructor(element) {
    this.element = element;
  }
  
  display(name) {
    this.updatingInput = true;
    this.inputValue = name;
    this.updatingInput = false;
  }
  
  getName(suggestion) {
    if (suggestion == null) {
      return '';
    }
    return this.service.getName(suggestion);
  }
  
  collapse() {
    this.expanded = false;
    this.index = -1;
  }
  
  select(suggestion) {
    this.value = suggestion;
    const name = this.getName(this.value);
    this.userInput = name;
    this.display(name);
    this.collapse();
  }
  
  valueChanged() {
    this.select(this.value);
  }
  
  inputValueChanged(value) {
    if (this.updatingInput) {
      return;
    }
    this.userInput = value;
    if (value === '') {
      this.value = null;
      this.collapse();
      return;
    }
    this.service.suggest(value)
      .then(suggestions => {
        this.index = -1;
        this.suggestions.splice(0, this.suggestions.length, ...suggestions);
        if (suggestions.length === 1) {
          this.select(suggestions[0]);
        } else if (suggestions.length === 0) {
          this.collapse();
        } else {
          this.expanded = true;
        }
      });
  }
  
  scroll() {
    const ul = this.suggestionsUL;
    const li = ul.children.item(this.index === -1 ? 0 : this.index);
    if (li.offsetTop + li.offsetHeight > ul.offsetHeight) {
      ul.scrollTop += li.offsetHeight;
    } else if(li.offsetTop < ul.scrollTop) {
      ul.scrollTop = li.offsetTop;
    }
  }
  
  keydown(key) {
    if (!this.expanded) {
      return true;
    }
    
    // down
    if (key === 40) {
      if (this.index < this.suggestions.length - 1) {
        this.index++;
        this.display(this.getName(this.suggestions[this.index]));
      } else {
        this.index = -1;
        this.display(this.userInput);
      } 
      this.scroll();
      return;
    }
    
    // up
    if (key === 38) {
      if (this.index === -1) {
        this.index = this.suggestions.length - 1;
        this.display(this.getName(this.suggestions[this.index]));
      } else if (this.index > 0) {
        this.index--;
        this.display(this.getName(this.suggestions[this.index]));
      } else {
        this.index = -1;
        this.display(this.userInput);
      }
      this.scroll();
      return;  
    }
    
    // escape
    if (key === 27) {
      this.display(this.userInput);
      this.collapse();
      return;
    }
    
    // enter
    if (key === 13) {
      if (this.index >= 0) {
        this.select(this.suggestions[this.index]);
      }
      return;
    }
    
    return true;
  }
  
  blur() {
    this.select(this.value);
    this.element.dispatchEvent(DOM.createCustomEvent('blur'));
  }
  
  suggestionClicked(suggestion) {
    this.select(suggestion);
  }
  
  focus() {
    this.element.firstElementChild.focus();
  }
}

// aria-activedescendant
// https://webaccessibility.withgoogle.com/unit?unit=6&lesson=13
// https://www.w3.org/TR/wai-aria/states_and_properties#aria-autocomplete
// https://www.w3.org/TR/wai-aria/roles#combobox

countries.js

export const countries = [ 
  {name: 'Afghanistan', code: 'AF'}, 
  {name: 'Åland Islands', code: 'AX'}, 
  {name: 'Albania', code: 'AL'}, 
  {name: 'Algeria', code: 'DZ'}, 
  {name: 'American Samoa', code: 'AS'}, 
  {name: 'AndorrA', code: 'AD'}, 
  {name: 'Angola', code: 'AO'}, 
  {name: 'Anguilla', code: 'AI'}, 
  {name: 'Antarctica', code: 'AQ'}, 
  {name: 'Antigua and Barbuda', code: 'AG'}, 
  {name: 'Argentina', code: 'AR'}, 
  {name: 'Armenia', code: 'AM'}, 
  {name: 'Aruba', code: 'AW'}, 
  {name: 'Australia', code: 'AU'}, 
  {name: 'Austria', code: 'AT'}, 
  {name: 'Azerbaijan', code: 'AZ'}, 
  {name: 'Bahamas', code: 'BS'}, 
  {name: 'Bahrain', code: 'BH'}, 
  {name: 'Bangladesh', code: 'BD'}, 
  {name: 'Barbados', code: 'BB'}, 
  {name: 'Belarus', code: 'BY'}, 
  {name: 'Belgium', code: 'BE'}, 
  {name: 'Belize', code: 'BZ'}, 
  {name: 'Benin', code: 'BJ'}, 
  {name: 'Bermuda', code: 'BM'}, 
  {name: 'Bhutan', code: 'BT'}, 
  {name: 'Bolivia', code: 'BO'}, 
  {name: 'Bosnia and Herzegovina', code: 'BA'}, 
  {name: 'Botswana', code: 'BW'}, 
  {name: 'Bouvet Island', code: 'BV'}, 
  {name: 'Brazil', code: 'BR'}, 
  {name: 'British Indian Ocean Territory', code: 'IO'}, 
  {name: 'Brunei Darussalam', code: 'BN'}, 
  {name: 'Bulgaria', code: 'BG'}, 
  {name: 'Burkina Faso', code: 'BF'}, 
  {name: 'Burundi', code: 'BI'}, 
  {name: 'Cambodia', code: 'KH'}, 
  {name: 'Cameroon', code: 'CM'}, 
  {name: 'Canada', code: 'CA'}, 
  {name: 'Cape Verde', code: 'CV'}, 
  {name: 'Cayman Islands', code: 'KY'}, 
  {name: 'Central African Republic', code: 'CF'}, 
  {name: 'Chad', code: 'TD'}, 
  {name: 'Chile', code: 'CL'}, 
  {name: 'China', code: 'CN'}, 
  {name: 'Christmas Island', code: 'CX'}, 
  {name: 'Cocos (Keeling) Islands', code: 'CC'}, 
  {name: 'Colombia', code: 'CO'}, 
  {name: 'Comoros', code: 'KM'}, 
  {name: 'Congo', code: 'CG'}, 
  {name: 'Congo, The Democratic Republic of the', code: 'CD'}, 
  {name: 'Cook Islands', code: 'CK'}, 
  {name: 'Costa Rica', code: 'CR'}, 
  {name: 'Cote D\'Ivoire', code: 'CI'}, 
  {name: 'Croatia', code: 'HR'}, 
  {name: 'Cuba', code: 'CU'}, 
  {name: 'Cyprus', code: 'CY'}, 
  {name: 'Czech Republic', code: 'CZ'}, 
  {name: 'Denmark', code: 'DK'}, 
  {name: 'Djibouti', code: 'DJ'}, 
  {name: 'Dominica', code: 'DM'}, 
  {name: 'Dominican Republic', code: 'DO'}, 
  {name: 'Ecuador', code: 'EC'}, 
  {name: 'Egypt', code: 'EG'}, 
  {name: 'El Salvador', code: 'SV'}, 
  {name: 'Equatorial Guinea', code: 'GQ'}, 
  {name: 'Eritrea', code: 'ER'}, 
  {name: 'Estonia', code: 'EE'}, 
  {name: 'Ethiopia', code: 'ET'}, 
  {name: 'Falkland Islands (Malvinas)', code: 'FK'}, 
  {name: 'Faroe Islands', code: 'FO'}, 
  {name: 'Fiji', code: 'FJ'}, 
  {name: 'Finland', code: 'FI'}, 
  {name: 'France', code: 'FR'}, 
  {name: 'French Guiana', code: 'GF'}, 
  {name: 'French Polynesia', code: 'PF'}, 
  {name: 'French Southern Territories', code: 'TF'}, 
  {name: 'Gabon', code: 'GA'}, 
  {name: 'Gambia', code: 'GM'}, 
  {name: 'Georgia', code: 'GE'}, 
  {name: 'Germany', code: 'DE'}, 
  {name: 'Ghana', code: 'GH'}, 
  {name: 'Gibraltar', code: 'GI'}, 
  {name: 'Greece', code: 'GR'}, 
  {name: 'Greenland', code: 'GL'}, 
  {name: 'Grenada', code: 'GD'}, 
  {name: 'Guadeloupe', code: 'GP'}, 
  {name: 'Guam', code: 'GU'}, 
  {name: 'Guatemala', code: 'GT'}, 
  {name: 'Guernsey', code: 'GG'}, 
  {name: 'Guinea', code: 'GN'}, 
  {name: 'Guinea-Bissau', code: 'GW'}, 
  {name: 'Guyana', code: 'GY'}, 
  {name: 'Haiti', code: 'HT'}, 
  {name: 'Heard Island and Mcdonald Islands', code: 'HM'}, 
  {name: 'Holy See (Vatican City State)', code: 'VA'}, 
  {name: 'Honduras', code: 'HN'}, 
  {name: 'Hong Kong', code: 'HK'}, 
  {name: 'Hungary', code: 'HU'}, 
  {name: 'Iceland', code: 'IS'}, 
  {name: 'India', code: 'IN'}, 
  {name: 'Indonesia', code: 'ID'}, 
  {name: 'Iran, Islamic Republic Of', code: 'IR'}, 
  {name: 'Iraq', code: 'IQ'}, 
  {name: 'Ireland', code: 'IE'}, 
  {name: 'Isle of Man', code: 'IM'}, 
  {name: 'Israel', code: 'IL'}, 
  {name: 'Italy', code: 'IT'}, 
  {name: 'Jamaica', code: 'JM'}, 
  {name: 'Japan', code: 'JP'}, 
  {name: 'Jersey', code: 'JE'}, 
  {name: 'Jordan', code: 'JO'}, 
  {name: 'Kazakhstan', code: 'KZ'}, 
  {name: 'Kenya', code: 'KE'}, 
  {name: 'Kiribati', code: 'KI'}, 
  {name: 'Korea, Democratic People\'S Republic of', code: 'KP'}, 
  {name: 'Korea, Republic of', code: 'KR'}, 
  {name: 'Kuwait', code: 'KW'}, 
  {name: 'Kyrgyzstan', code: 'KG'}, 
  {name: 'Lao People\'S Democratic Republic', code: 'LA'}, 
  {name: 'Latvia', code: 'LV'}, 
  {name: 'Lebanon', code: 'LB'}, 
  {name: 'Lesotho', code: 'LS'}, 
  {name: 'Liberia', code: 'LR'}, 
  {name: 'Libyan Arab Jamahiriya', code: 'LY'}, 
  {name: 'Liechtenstein', code: 'LI'}, 
  {name: 'Lithuania', code: 'LT'}, 
  {name: 'Luxembourg', code: 'LU'}, 
  {name: 'Macao', code: 'MO'}, 
  {name: 'Macedonia, The Former Yugoslav Republic of', code: 'MK'}, 
  {name: 'Madagascar', code: 'MG'}, 
  {name: 'Malawi', code: 'MW'}, 
  {name: 'Malaysia', code: 'MY'}, 
  {name: 'Maldives', code: 'MV'}, 
  {name: 'Mali', code: 'ML'}, 
  {name: 'Malta', code: 'MT'}, 
  {name: 'Marshall Islands', code: 'MH'}, 
  {name: 'Martinique', code: 'MQ'}, 
  {name: 'Mauritania', code: 'MR'}, 
  {name: 'Mauritius', code: 'MU'}, 
  {name: 'Mayotte', code: 'YT'}, 
  {name: 'Mexico', code: 'MX'}, 
  {name: 'Micronesia, Federated States of', code: 'FM'}, 
  {name: 'Moldova, Republic of', code: 'MD'}, 
  {name: 'Monaco', code: 'MC'}, 
  {name: 'Mongolia', code: 'MN'}, 
  {name: 'Montserrat', code: 'MS'}, 
  {name: 'Morocco', code: 'MA'}, 
  {name: 'Mozambique', code: 'MZ'}, 
  {name: 'Myanmar', code: 'MM'}, 
  {name: 'Namibia', code: 'NA'}, 
  {name: 'Nauru', code: 'NR'}, 
  {name: 'Nepal', code: 'NP'}, 
  {name: 'Netherlands', code: 'NL'}, 
  {name: 'Netherlands Antilles', code: 'AN'}, 
  {name: 'New Caledonia', code: 'NC'}, 
  {name: 'New Zealand', code: 'NZ'}, 
  {name: 'Nicaragua', code: 'NI'}, 
  {name: 'Niger', code: 'NE'}, 
  {name: 'Nigeria', code: 'NG'}, 
  {name: 'Niue', code: 'NU'}, 
  {name: 'Norfolk Island', code: 'NF'}, 
  {name: 'Northern Mariana Islands', code: 'MP'}, 
  {name: 'Norway', code: 'NO'}, 
  {name: 'Oman', code: 'OM'}, 
  {name: 'Pakistan', code: 'PK'}, 
  {name: 'Palau', code: 'PW'}, 
  {name: 'Palestinian Territory, Occupied', code: 'PS'}, 
  {name: 'Panama', code: 'PA'}, 
  {name: 'Papua New Guinea', code: 'PG'}, 
  {name: 'Paraguay', code: 'PY'}, 
  {name: 'Peru', code: 'PE'}, 
  {name: 'Philippines', code: 'PH'}, 
  {name: 'Pitcairn', code: 'PN'}, 
  {name: 'Poland', code: 'PL'}, 
  {name: 'Portugal', code: 'PT'}, 
  {name: 'Puerto Rico', code: 'PR'}, 
  {name: 'Qatar', code: 'QA'}, 
  {name: 'Reunion', code: 'RE'}, 
  {name: 'Romania', code: 'RO'}, 
  {name: 'Russian Federation', code: 'RU'}, 
  {name: 'RWANDA', code: 'RW'}, 
  {name: 'Saint Helena', code: 'SH'}, 
  {name: 'Saint Kitts and Nevis', code: 'KN'}, 
  {name: 'Saint Lucia', code: 'LC'}, 
  {name: 'Saint Pierre and Miquelon', code: 'PM'}, 
  {name: 'Saint Vincent and the Grenadines', code: 'VC'}, 
  {name: 'Samoa', code: 'WS'}, 
  {name: 'San Marino', code: 'SM'}, 
  {name: 'Sao Tome and Principe', code: 'ST'}, 
  {name: 'Saudi Arabia', code: 'SA'}, 
  {name: 'Senegal', code: 'SN'}, 
  {name: 'Serbia and Montenegro', code: 'CS'}, 
  {name: 'Seychelles', code: 'SC'}, 
  {name: 'Sierra Leone', code: 'SL'}, 
  {name: 'Singapore', code: 'SG'}, 
  {name: 'Slovakia', code: 'SK'}, 
  {name: 'Slovenia', code: 'SI'}, 
  {name: 'Solomon Islands', code: 'SB'}, 
  {name: 'Somalia', code: 'SO'}, 
  {name: 'South Africa', code: 'ZA'}, 
  {name: 'South Georgia and the South Sandwich Islands', code: 'GS'}, 
  {name: 'Spain', code: 'ES'}, 
  {name: 'Sri Lanka', code: 'LK'}, 
  {name: 'Sudan', code: 'SD'}, 
  {name: 'Suriname', code: 'SR'}, 
  {name: 'Svalbard and Jan Mayen', code: 'SJ'}, 
  {name: 'Swaziland', code: 'SZ'}, 
  {name: 'Sweden', code: 'SE'}, 
  {name: 'Switzerland', code: 'CH'}, 
  {name: 'Syrian Arab Republic', code: 'SY'}, 
  {name: 'Taiwan, Province of China', code: 'TW'}, 
  {name: 'Tajikistan', code: 'TJ'}, 
  {name: 'Tanzania, United Republic of', code: 'TZ'}, 
  {name: 'Thailand', code: 'TH'}, 
  {name: 'Timor-Leste', code: 'TL'}, 
  {name: 'Togo', code: 'TG'}, 
  {name: 'Tokelau', code: 'TK'}, 
  {name: 'Tonga', code: 'TO'}, 
  {name: 'Trinidad and Tobago', code: 'TT'}, 
  {name: 'Tunisia', code: 'TN'}, 
  {name: 'Turkey', code: 'TR'}, 
  {name: 'Turkmenistan', code: 'TM'}, 
  {name: 'Turks and Caicos Islands', code: 'TC'}, 
  {name: 'Tuvalu', code: 'TV'}, 
  {name: 'Uganda', code: 'UG'}, 
  {name: 'Ukraine', code: 'UA'}, 
  {name: 'United Arab Emirates', code: 'AE'}, 
  {name: 'United Kingdom', code: 'GB'}, 
  {name: 'United States', code: 'US'}, 
  {name: 'United States Minor Outlying Islands', code: 'UM'}, 
  {name: 'Uruguay', code: 'UY'}, 
  {name: 'Uzbekistan', code: 'UZ'}, 
  {name: 'Vanuatu', code: 'VU'}, 
  {name: 'Venezuela', code: 'VE'}, 
  {name: 'Viet Nam', code: 'VN'}, 
  {name: 'Virgin Islands, British', code: 'VG'}, 
  {name: 'Virgin Islands, U.S.', code: 'VI'}, 
  {name: 'Wallis and Futuna', code: 'WF'}, 
  {name: 'Western Sahara', code: 'EH'}, 
  {name: 'Yemen', code: 'YE'}, 
  {name: 'Zambia', code: 'ZM'}, 
  {name: 'Zimbabwe', code: 'ZW'} 
];

index.html

<!doctype html>
<html>
  <head>
    <title>Aurelia</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/meyer-reset/2.0/reset.min.css">
    <style>
      .form-component {
        display: block;
      }
    </style>
  </head>
  <body aurelia-app>
    <h1>Loading...</h1>
    
    <script src="https://jdanyow.github.io/rjs-bundle/node_modules/requirejs/require.js"></script>
    <script src="https://jdanyow.github.io/rjs-bundle/config.js"></script>
    <script src="https://jdanyow.github.io/rjs-bundle/bundles/aurelia.js"></script>
    <script src="https://jdanyow.github.io/rjs-bundle/bundles/babel.js"></script>
    <script>
      require(['aurelia-bootstrapper']);
    </script>
  </body>
</html>