paper-typeahead-input.html

<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../paper-input/paper-input.html">
<link rel="import" href="../paper-menu/paper-menu.html">
<link rel="import" href="../paper-item/paper-item.html">
<link rel="import" href="../iron-ajax/iron-ajax.html">
<link rel="import" href="../paper-material/paper-material.html">

<!--
paper-typeahead-input is an element providing typeahead feature for input.

Basic use of paper-typeahead-input. Use a predefined list of suggestions.

    <paper-typeahead-input label="US states" local-candidates="{{states}}"
     placeholder="Please enter value" max-suggestions="4">
    </paper-typeahead-input>

For now, there are three types of sources for suggetions. localCandidates, prefetchUrl, and remoteUrl. The candidates combined from these three ways becomes the potential candidates for input.


<b>Installation</b>

Install with bower

    bower install paper-typeahead-input

If you want to save it in bower.json file, remember to add flag --save

    bower install --save paper-typeahead-input

@demo
-->
<dom-module id="paper-typeahead-input">

  <style>
    :host {
      display: block;
      box-sizing: border-box;
    }
    paper-material{
      left:0;
      right:0;
      position: absolute;
      z-index: 10;
    }
    paper-item{
      cursor: pointer;
    }
    .iron-selected{
      background: #E0E0E0;
    }
    .typeahead{
      font-family: 'Roboto', 'Noto', sans-serif;
      -webkit-font-smoothing: antialiased;
      font-size: 16px;
      font-weight: 400;
      line-height: 24px;color: #737373;
    }
    .typeahead::first-letter{
      visibility: hidden;
    }
    .typeahead-with-label{
      position:absolute;
      top:12px;
    }
    .typeahead-without-label{
      position:absolute;
      top:-8px;
    }
  </style>

  <template>
    <template is="dom-if" if="{{label}}">
     <h3>{{label}}</h3>
    </template>
    <template is="dom-if" if="{{prefetchUrl}}">
    <iron-ajax
    auto
    url="{{prefetchUrl}}"
    handle-as="json"
    last-response="{{_prefetchedCandidates}}"
    ></iron-ajax>
    </template>

   <div style="position:relative;">
    <p class$="typeahead {{_getTypeaheadClasses(noLabelFloat)}}">{{_getTypeaheadDisplay(_typeahead)}}</p>
    <paper-input value="{{inputValue}}" on-keyup="_keyup" on-keydown="_keydown"  label="{{placeholder}}"
      always-float-label="{{alwaysFloatLabel}}"
      autofocus="{{autofocus}}"
      char-counter="{{charCounter}}"
      disabled="{{disabled}}"
      error-message="{{errorMessage}}"
      maxlength="{{maxlength}}"
      minlength="{{minlength}}"
      no-label-float="{{noLabelFloat}}"
      readonly="{{readonly}}"
      required="{{required}}"
      auto-validate="{{autoValidate}}"
      pattern="{{pattern}}"
    ></paper-input>

    <template is="dom-if" if="{{suggestions.length}}">
    <paper-material >
    <paper-menu on-iron-select="_itemSelect">
      <template is="dom-repeat" items="{{suggestions}}">
        <template is="dom-if" if="{{isCandidatesJson}}">
          <paper-item on-mouseover="_selection" on-tap="_select">
           <span>{{_getDisplayValue(item)}}</span>
          </paper-item>
        </template>
        <template is="dom-if" if="{{!isCandidatesJson}}">
          <paper-item on-mouseover="_selection" on-tap="_select">
           <span>{{item}}</span>
          </paper-item>
        </template>
      </template>
    </paper-menu>
    </paper-material>

   </template>
  </div>
  </template>

</dom-module>

<script>

  Polymer({

    is: 'paper-typeahead-input',
    /**
     * Fired when an item in the suggestion list is selected, either by up and down key or hover by mouse.
     *
     * @event pt-item-select
     */
    /**
     * Fired when an item in the suggestion list is confirmed, either by hit enter key where element selected or clicked on the element directly by mouse.
     *
     * @event pt-item-confirmed
     */
     /**
     * Fired when remoteUrl is set up and http request on remoteUrl is scheduled to send ( depends on remoteUrlWaitMs setting).
     *
     * @event pt-remote-searching-start
     */
     /**
     * Fired when remoteUrl is set up and http request on remoteUrl is finished.
     *
     * @event pt-remote-searching-end
     */
    properties: {

      /**
       * The label that will show up as the label for tags input. It not specified, no label will show up.
       */
      label:{
        type:String,
        value:''
      },
      /**
       * The placeholder for the paper-input element.
       */
      placeholder:{
        type:String,
        value:'Please enter values here'
      },
      /**
       * The candidates from local variable.
       */
      localCandidates:{
        type:Array,
        value:[]
      },
      /**
       * Url for a prefectched list in json format for the list of suggestion candidates. The response should be something like: ["a","b"]
       */
      prefetchUrl:String,
      /**
      * The prefetched candidates get by prefetchUrl
      */
      _prefetchedCandidates:{
        type:Array,
        value:[]
      },
      /**
       * Internal variable holding all matched suggestions.
       */
      suggestions:{
        type:Array,
        readOnly:true,
        value:[]
      },
      /**
       * Internal variable holding all matched suggestions.
       */
      _typeahead:{
        type:String,
        value:""
      },
      /**
       * Maximum number of suggestions to show up in typeahead.
       */
      maxSuggestions:{
        type:Number,
        value:5
      },
      /**
       * Remote url to perform a search using the value in the input. The input value will be passed in as url parameter. The placeholder should be %QUERY.
       */
      remoteUrl:String,
       /**
       * Number of milliseconds to wait after user types a character.
       * This is helpful to reduce number of calls to remoteUrl based on performance consideration if it's set up properly based on how fast user usually types.
       * Default is undefined which means the search request to remoteUrl will be fired immediately after user types a character.
       * This propery only makes sense if remoteUrl is set up.
       */
      remoteUrlWaitMs:{
        type:Number,
        value:undefined
      },
      /**
       * A boolean property to indicate if elements in the candidates list are json dictionary.
       * When this property set up to be true, the candidates will be treated as list of json objects. Otherwise will be treated as list of strings.
       */
      isCandidatesJson:{
        type:Boolean,
        value:false
      },
      /**
       * An array to tell what property in the json object of candidate is searchable.
       * This property only makes sense when property isCandidatesJson set to be true.
       */
      searchableProps:{
        type:Array,
        value:[]
      },
      /**
        * The property in json object that should be chosen for the paper-input value when an element is selected from the suggestions.
        * This property only makes sense when property isCandidatesJson set to be true.
        */
      displayProp:{
        type:String,
        value:undefined
      },
      /**
       * A boolean property to indicate if there is a searching going on to remoteUrl.
       * This propery only makes sense if remoteUrl is set up.
       */
      remoteUrlSearching:{
        type:Boolean,
        value:false,
        notify:true
      },
      /**
       * Input value.
       */
      inputValue:{
        type:String,
        notify:true
      },
      /**
       * Input object.
       */
      inputObject:{
        type:Object,
        notify:true
      },
      /**
       * Bind this to the <paper-input>'s alwaysFloatLabel property.
       */
      alwaysFloatLabel:Boolean,
      /**
       * Bind this to the <paper-input>'s autofocus property.
       */
      autofocus:Boolean,
      /**
       * Bind this to the <paper-input>'s charCounter property.
       */
      charCounter:Boolean,
      /**
       * Bind this to the <paper-input>'s disabled property.
       */
      disabled:Boolean,
      /**
       * Bind this to the <paper-input>'s errorMessage property.
       */
      errorMessage:String,
      /**
       * Bind this to the <paper-input>'s maxlength property.
       */
      maxlength:Number,
      /**
       * Bind this to the <paper-input>'s minlength property.
       */
      minlength:Number,
      /**
       * Bind this to the <paper-input>'s noLabelFloat property.
       */
      noLabelFloat:{
        type:Boolean,
        value:false
      },
      /**
       * Bind this to the <paper-input>'s readonly property.
       */
      readonly:Boolean,
      /**
       * Bind this to the <paper-input>'s required property.
       */
      required:Boolean,
      /**
       * Bind this to the <paper-input>'s autoValidate property.
       */
      autoValidate:Boolean,
      /**
       * Bind this to the <paper-input>'s pattern property.
       */
      pattern:String
    },

    // Element Lifecycle

    ready: function() {
      // `ready` is called after all elements have been configured, but
      // propagates bottom-up. This element's children are ready, but parents
      // are not.
      //
      // This is the point where you should make modifications to the DOM (when
      // necessary), or kick off any processes the element wants to perform.
      document.addEventListener("click", function(){
        var ptinputs = document.querySelectorAll('paper-typeahead-input')
        for (var i = 0; i < ptinputs.length; i ++){
          var ptinput = ptinputs[i];
          ptinput._setSuggestions([]);
        }
      });
      var input = Polymer.dom(this.root).querySelector('paper-input');
      input.$.input.autocomplete = 'address-level4';
    },

    attached: function() {
      // `attached` fires once the element and its parents have been inserted
      // into a document.
      //
      // This is a good place to perform any work related to your element's
      // visual state or active behavior (measuring sizes, beginning animations,
      // loading resources, etc).
    },

    detached: function() {
      // The analog to `attached`, `detached` fires when the element has been
      // removed from a document.
      //
      // Use this to clean up anything you did in `attached`.
    },
    /**
     * Focus on the paper-input element inside of paper-typeahead-input.
     */
    focus: function() {
      var input = Polymer.dom(this.root).querySelector('paper-input');
      input.focus();
    },
    _getTypeaheadDisplay:function(_typeahead){
      var input = this._getInputValue();
      if (input != "" && typeof(_typeahead) != 'undefined' && _typeahead !='') {
        return input.substring(0,1) + _typeahead.substring(1);
      }
      return "";
    },
    _getTypeaheadClasses:function(noLabelFloat){
      if (noLabelFloat && typeof(noLabelFloat) != 'undefined' && noLabelFloat == true) {
        return "typeahead-without-label";
      }
      return "typeahead-with-label";
    },
    _itemSelect:function(e, detail){
      this.fire('pt-item-select',detail);
    },
    // Element Behavior
    /**
     * Callback for keydown event
     *
     * @param {e} event
     */
    _keydown: function(e) {
      if (e.which == 40 || e.which == 38){
          e.preventDefault();
      }
      else if (e.which == 9) {
         //tab key
        if (this._typeahead && typeof(this._typeahead)!= 'undefined' && this._typeahead != ''){
          e.preventDefault();
          if (this.isCandidatesJson == true){
            //if a typeahead is available it's always the first element of the candidates
            this.inputObject = this.suggestions[0];
            this.inputValue = this._getDisplayValue(this.inputObject);
          }
          else{
            this.inputValue = this._typeahead;
          }
          var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
          var selectedItem = suggestionsMenu[0];
          this._setSuggestions([]);
          this.fire('pt-item-confirmed',selectedItem);
          this._typeahead = "";
        }
      }
    },
    /**
     * Callback on mouseover event on paper-item
     *
     */
    _selection:function(e){
      var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
      if (suggestionsMenu && typeof(suggestionsMenu) != 'undefined'){
        var selectedItem = e.currentTarget;
        index = Number(suggestionsMenu.indexOf(selectedItem));
        suggestionsMenu.select(index);
        var input = Polymer.dom(this.root).querySelector('paper-input');
        input.focus();
      }
      else{
        console.log("suggestionsMenu not defined");
      }
    },
    /**
     * Return inputValue
     * @return {[type]} [description]
     */
    _getInputValue: function() {
      if (this.inputValue && typeof(this.inputValue) != 'undefined'){
        return this.inputValue.trim();
      }
      return "";
    },
    /**
     * Update the text to show for typeahead
     */
    _updateTypeahead: function() {
      if (this.suggestions.length == 0){
        this._typeahead = "";
        return;
      }
      var firstSuggestion = this.suggestions[0];

      if (this.isCandidatesJson == true){ //then use the display property
        firstSuggestion = this._getDisplayValue(firstSuggestion);
      }

      if (this._getInputValue() == "") {
        this._typeahead = "";
        return;
      }
      if (firstSuggestion.toLowerCase().indexOf(this._getInputValue().toLowerCase())!=0) {
        this._typeahead = "";
        return;
      }
      this._typeahead = firstSuggestion;
    },
    /**
     * Callback on click event on paper-item
     */
    _select: function(e) {
      var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
      if (suggestionsMenu && typeof(suggestionsMenu) != 'undefined'){
        var selectedItem = e.currentTarget;
        index = Number(suggestionsMenu.indexOf(selectedItem));

        if (this.isCandidatesJson == true){
          this.inputObject = this.suggestions[index];
          this.inputValue = this._getDisplayValue(this.inputObject);
        }
        else{
          this.inputValue = this.suggestions[index];
        }

        this._setSuggestions([]);
        this.fire('pt-item-confirmed',e.target);
        this._typeahead = "";
        e.stopPropagation();
      }
      else{
        console.log("suggestionsMenu not defined");
      }
    },
    /**
     * Callback for keyup event
     *
     * @param {e} event
     */
    _keyup: function(e) {
      if (e.which == 40){
        //down button
        var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
        var selectedItem = suggestionsMenu.focusedItem;
        var index = 0;
        if (typeof(selectedItem) != 'undefined'){
          index = Number(suggestionsMenu.indexOf(selectedItem));
          index = Math.min(index + 1, this.suggestions.length - 1);
        }
        suggestionsMenu.select(index);
        var input = Polymer.dom(this.root).querySelector('paper-input');
        input.focus();
      }
      else if (e.which == 38){
        //up
        var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
        var selectedItem = suggestionsMenu.focusedItem;
        if (typeof(selectedItem) != 'undefined'){
          index = Number(suggestionsMenu.indexOf(selectedItem));
          index = Math.max(index - 1, -1);
          suggestionsMenu.select(index);
        }
        var input = Polymer.dom(this.root).querySelector('paper-input');
        input.focus();
      }
      else if (e.which == 13){
        var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
        if (suggestionsMenu && typeof(suggestionsMenu) != 'undefined'){
          var selectedItem = suggestionsMenu.focusedItem;
          if (typeof(selectedItem) != 'undefined'){
            index = Number(suggestionsMenu.indexOf(selectedItem));

            if (this.isCandidatesJson == true){
              this.inputObject = this.suggestions[index];
              this.inputValue = this._getDisplayValue(this.inputObject);
            }
            else{
              this.inputValue = this.suggestions[index];
            }
            this._setSuggestions([]);
            this.fire('pt-item-confirmed',selectedItem);
            this._typeahead = "";
          }
        }
      }
      else if (e.which == 9){
        //prevent fire search for tab key
      }
      else{
        var suggestionsMenu = Polymer.dom(this.root).querySelector('paper-menu');
        if (suggestionsMenu && typeof(suggestionsMenu) != 'undefined'){
          suggestionsMenu.select(-1);
        }
        // if (this.inputValue.length >= 3){
        this._search(this.inputValue.trim());
        // this.suggestions = this._search(this.inputValue.trim());
        // }
      }
    },
    _getDisplayValue:function(item){
      if (this.displayProp && typeof(this.displayProp) != 'undefined'){
        return item[this.displayProp];
      }
      else{
        console.log("paper-typeahead-input: displayProp not set up");
        return "";
      }
    },
    _getTestCandidate:function(item){
      if (this.isCandidatesJson == true){
        var toTest = [];
        for (var i = 0; i < this.searchableProps.length; i ++){
          if (item[this.searchableProps[i]] != "undefined"){
            toTest.push(item[this.searchableProps[i]]);
          }
        }
        return toTest;
      }
      else{
        return [item];
      }
    },
    _search:function(term){
      if (term == ""){
        this._setSuggestions([]);
        this._updateTypeahead();
        return;
      }
      var patt =  new RegExp(term.toLowerCase());
      var matched = [];

      if (typeof(this.localCandidates) != 'undefined'){
        for (var i = 0; i < this.localCandidates.length; i ++){
          if (matched.length == this.maxSuggestions){
            break;
          }
          var toTest = this._getTestCandidate(this.localCandidates[i]);
          for (var j = 0; j < toTest.length; j ++){
            var item = toTest[j];
            if (patt.test(item.toLowerCase()) == true){
              matched.push(this.localCandidates[i]);
              break;
            }
          }
        }
      }
      if (typeof(this._prefetchedCandidates) != 'undefined'){
        for (var i = 0; i < this._prefetchedCandidates.length; i ++){
          if (matched.length == this.maxSuggestions){
            break;
          }
          var toTest = this._getTestCandidate(this._prefetchedCandidates[i]);
          for (var j = 0; j < toTest.length; j ++){
            var item = toTest[j];
            if (patt.test(item.toLowerCase()) == true){
              matched.push(this._prefetchedCandidates[i]);
              break;
            }
          }
        }
      }
      // this.suggestions = this.suggestions.concat(matched);
      if (typeof(this.remoteUrl) != 'undefined'){
        var pt_element = this;
        pt_element.fire('pt-remote-searching-start',pt_element);
        pt_element.remoteUrlSearching = true;
        this.debounce('remoteUrlSearch', function(){
          var url = pt_element.remoteUrl.replace("%QUERY", term);
          var xmlhttp = new XMLHttpRequest();
          xmlhttp.open('GET', url, true);
          xmlhttp.setRequestHeader("Content-type", "application/json");
          var ptinput = pt_element;
          xmlhttp.onreadystatechange = function() {
              if (xmlhttp.readyState === 4) {
                if (xmlhttp.status == 200){
                    var resp = xmlhttp.response;
                    var remoteMatched = JSON.parse(resp);
                    var cuttedMatched = remoteMatched.slice(0,ptinput.maxSuggestions);
                    matched = matched.concat(cuttedMatched);
                    ptinput._setSuggestions(matched);
                }
                pt_element.remoteUrlSearching = false;
                pt_element.fire('pt-remote-searching-end',pt_element);
              }


          }
          xmlhttp.send();
        }, this.remoteUrlWaitMs);
      }
      else{
        this._setSuggestions(matched);
      }
      this._updateTypeahead();
    }//_search

  });

</script>