px-accordion-group.html

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    Relative paths assume component is being run from inside an app or another component, where dependencies are flat
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<link rel="import" href="../polymer/polymer.html" />
<link rel="import" href="css/px-accordion-styles.html" />
<link rel="import" href="../app-localize-behavior/app-localize-behavior.html" />
<!--

@blurb renders a accordion component
@homepage index.html
@demo index.html
-->

<dom-module id="px-accordion-group">
  <template>
    <style include="px-accordion-styles"></style>
    <div class="accordion__expand__collapse text--right">
      <span data-val="expand" class$="accordion__expand {{_getBtnClassName(_expandAllActive)}}" on-tap="_handleExpandAll">{{localize('Expand All')}}</span>
      <span> | </span>
      <span data-val="collapse" class$="accordion__collapse {{_getBtnClassName(_collapseAllActive)}}" on-tap="_handleCollapseAll">{{localize('Collapse All')}}</span>
    </div>
    <slot id="accordions"></slot>
  </template>
  <script>
    Polymer({
      is: 'px-accordion-group',

      behaviors: [ Polymer.AppLocalizeBehavior ],

      properties: {
        /**
         * A valid IETF language tag as a string that `app-localize-behavior` will
         * use to localize this component.
         *
         * See https://github.com/PolymerElements/app-localize-behavior for API
         * documentation and more information.
         */
        language: {
          type: String,
          value: 'en'
        },
        /**
        * Use the key for localization if value for  language is missing. Should
        * always be true for our components.
        */
        useKeyIfMissing: {
          type: Boolean,
          value: true
        },
        resources: {
          type: Object,
          value: function() {
            return {
              'en': {
                "Expand All": "Expand All",
                "Collapse All": "Collapse All"
              }
            }
          }
        },
        _expandAllActive: {
          type: Boolean,
          value: false
        },
        _collapseAllActive: {
          type: Boolean,
          value: false
        },
        _accordions: {
          type: Array,
          value: null,
          observer: '_updateAccordionState'
        }
      },

      listeners: {
        'px-accordion-opened-state-changed' : '_updateAccordionState'
      },

      attached: function() {
        var boundHandler = this._getChildAccordions.bind(this);
        this._observer = Polymer.dom(this.$.accordions).observeNodes(boundHandler);
      },

      detached: function() {
        Polymer.dom(this.$.accordions).unobserveNodes(this._observer);
        this._accordions = null;
      },

      _getBtnClassName: function(active) {
        return active ? 'actionable' : 'actionable--disabled';
      },

      _getChildAccordions: function() {
        this.debounce('get-child-accordions', function() {
          this._accordions = this.queryAllEffectiveChildren('px-accordion');
        }, 1);
      },

      _updateAccordionState: function() {
        this.debounce('update-accordion-state', function() {
          if (this._accordions && Array.isArray(this._accordions) && this._accordions.length > 0) {
            let anyExpanded = false;
            let anyCollapsed = false;
            for (let i=0; i<this._accordions.length; i++) {
              if (anyExpanded && anyCollapsed) {
                break;
              }
              if (this._accordions[i].opened === true) {
                anyExpanded = true;
              }
              if (this._accordions[i].opened === false) {
                anyCollapsed = true;
              }
            }
            this._expandAllActive = anyCollapsed;
            this._collapseAllActive = anyExpanded;
          }
        }, 1);
      },

      _handleExpandAll: function() {
        if (this._accordions && Array.isArray(this._accordions) && this._accordions.length > 0) {
          for (let i=0; i<this._accordions.length; i++) {
            this._accordions[i].opened = true;
          }
        }
      },

      _handleCollapseAll: function() {
        if (this._accordions && Array.isArray(this._accordions) && this._accordions.length > 0) {
          for (let i=0; i<this._accordions.length; i++) {
            this._accordions[i].opened = false;
          }
        }
      }
    });
  </script>
</dom-module>