[polymer] interop with polymer-element and polymer.js

samples/third_party/todomvc/web/lib-elements/polymer-selector.html

+<!--
+Copyright 2013 The Polymer Authors. All rights reserved.
+Use of this source code is governed by a BSD-style
+license that can be found in the LICENSE file.
+-->
+<!--
+/**
+ * @module Polymer Elements
+ */
+/**
+ * polymer-selector is used to manage a list of elements that can be selected.
+ * The attribute "selected" indicates which item element is being selected.
+ * The attribute "multi" indicates if multiple items can be selected at once.
+ * Tapping on the item element would fire "polymer-activate" event. Use
+ * "polymer-select" event to listen for selection changes.
+ *
+ * Example:
+ *
+ *     <polymer-selector selected="0">
+ *       <div>Item 1</div>
+ *       <div>Item 2</div>
+ *       <div>Item 3</div>
+ *     </polymer-selector>
+ *
+ * polymer-selector is not styled.  So one needs to use "polymer-selected" CSS
+ * class to style the selected element.
+ *
+ *     <style>
+ *       .item.polymer-selected {
+ *         background: #eee;
+ *       }
+ *     </style>
+ *     ...
+ *     <polymer-selector>
+ *       <div class="item">Item 1</div>
+ *       <div class="item">Item 2</div>
+ *       <div class="item">Item 3</div>
+ *     </polymer-selector>
+ *
+ * @class polymer-selector
+ */
+/**
+ * Fired when an item's selection state is changed. This event is fired both
+ * when an item is selected or deselected. The `isSelected` detail property
+ * contains the selection state.
+ *
+ * @event polymer-select
+ * @param {Object} detail
+ *   @param {boolean} detail.isSelected true for selection and false for deselection
+ *   @param {Object} detail.item the item element
+ */
+/**
+ * Fired when an item element is tapped.
+ *
+ * @event polymer-activate
+ * @param {Object} detail
+ *   @param {Object} detail.item the item element
+ */
+-->
+<link rel="import" href="polymer-selection.html">
+
+<polymer-element name="polymer-selector"
+    attributes="selected multi valueattr selectedClass selectedProperty selectedItem selectedModel selectedIndex notap target itemsSelector activateEvent">
+  <template>
+    <polymer-selection id="selection" multi="{{multi}}" on-polymer-select="{{selectionSelect}}"></polymer-selection>
+    <content id="items" select="*"></content>
+  </template>
+  <script>
+    Polymer('polymer-selector', {
+      /**
+       * Gets or sets the selected element.  Default to use the index
+       * of the item element.
+       *
+       * If you want a specific attribute value of the element to be
+       * used instead of index, set "valueattr" to that attribute name.
+       *
+       * Example:
+       *
+       *     <polymer-selector valueattr="label" selected="foo">
+       *       <div label="foo"></div>
+       *       <div label="bar"></div>
+       *       <div label="zot"></div>
+       *     </polymer-selector>
+       *
+       * In multi-selection this should be an array of values.
+       *
+       * Example:
+       *
+       *     <polymer-selector id="selector" valueattr="label" multi>
+       *       <div label="foo"></div>
+       *       <div label="bar"></div>
+       *       <div label="zot"></div>
+       *     </polymer-selector>
+       *
+       *     this.$.selector.selected = ['foo', 'zot'];
+       *
+       * @attribute selected
+       * @type Object
+       * @default null
+       */
+      selected: null,
+      /**
+       * If true, multiple selections are allowed.
+       *
+       * @attribute multi
+       * @type boolean
+       * @default false
+       */
+      multi: false,
+      /**
+       * Specifies the attribute to be used for "selected" attribute.
+       *
+       * @attribute valueattr
+       * @type string
+       * @default 'name'
+       */
+      valueattr: 'name',
+      /**
+       * Specifies the CSS class to be used to add to the selected element.
+       *
+       * @attribute selectedClass
+       * @type string
+       * @default 'polymer-selected'
+       */
+      selectedClass: 'polymer-selected',
+      /**
+       * Specifies the property to be used to set on the selected element
+       * to indicate its active state.
+       *
+       * @attribute selectedProperty
+       * @type string
+       * @default 'active'
+       */
+      selectedProperty: 'active',
+      /**
+       * Returns the currently selected element. In multi-selection this returns
+       * an array of selected elements.
+       *
+       * @attribute selectedItem
+       * @type Object
+       * @default null
+       */
+      selectedItem: null,
+      /**
+       * In single selection, this returns the model associated with the
+       * selected element.
+       *
+       * @attribute selectedModel
+       * @type Object
+       * @default null
+       */
+      selectedModel: null,
+      /**
+       * In single selection, this returns the selected index.
+       *
+       * @attribute selectedIndex
+       * @type number
+       * @default -1
+       */
+      selectedIndex: -1,
+      /**
+       * The target element that contains items.  If this is not set
+       * polymer-selector is the container.
+       *
+       * @attribute target
+       * @type Object
+       * @default null
+       */
+      target: null,
+      /**
+       * This can be used to query nodes from the target node to be used for
+       * selection items.  Note this only works if the 'target' property is set.
+       *
+       * Example:
+       *
+       *     <polymer-selector target="{{$.myForm}}" itemsSelector="input[type=radio]"></polymer-selector>
+       *     <form id="myForm">
+       *       <label><input type="radio" name="color" value="red"> Red</label> <br>
+       *       <label><input type="radio" name="color" value="green"> Green</label> <br>
+       *       <label><input type="radio" name="color" value="blue"> Blue</label> <br>
+       *       <p>color = {{color}}</p>
+       *     </form>
+       *
+       * @attribute itemSelector
+       * @type string
+       * @default ''
+       */
+      itemsSelector: '',
+      /**
+       * The event that would be fired from the item element to indicate
+       * it is being selected.
+       *
+       * @attribute activateEvent
+       * @type string
+       * @default 'tap'
+       */
+      activateEvent: 'tap',
+      notap: false,
+      ready: function() {
+        this.activateListener = this.activateHandler.bind(this);
+        this.observer = new MutationObserver(this.updateSelected.bind(this));
+        if (!this.target) {
+          this.target = this;
+        }
+      },
+      get items() {
+        var nodes = this.target !== this ? (this.itemsSelector ?
+            this.target.querySelectorAll(this.itemsSelector) :
+                this.target.children) : this.$.items.getDistributedNodes();
+        return Array.prototype.filter.call(nodes || [], function(n) {
+          return n && n.localName !== 'template';
+        });
+      },
+      targetChanged: function(old) {
+        if (old) {
+          this.removeListener(old);
+          this.observer.disconnect();
+        }
+        if (this.target) {
+          this.addListener(this.target);
+          this.observer.observe(this.target, {childList: true});
+        }
+      },
+      addListener: function(node) {
+        node.addEventListener(this.activateEvent, this.activateListener);
+      },
+      removeListener: function(node) {
+        node.removeEventListener(this.activateEvent, this.activateListener);
+      },
+      get selection() {
+        return this.$.selection.getSelection();
+      },
+      selectedChanged: function() {
+        this.updateSelected();
+      },
+      updateSelected: function() {
+        this.validateSelected();
+        if (this.multi) {
+          this.clearSelection();
+          this.selected && this.selected.forEach(function(s) {
+            this.valueToSelection(s);
+          }, this);
+        } else {
+          this.valueToSelection(this.selected);
+        }
+      },
+      validateSelected: function() {
+        // convert to an array for multi-selection
+        if (this.multi && !Array.isArray(this.selected) &&
+            this.selected !== null && this.selected !== undefined) {
+          this.selected = [this.selected];
+        }
+      },
+      clearSelection: function() {
+        if (this.multi) {
+          this.selection.slice().forEach(function(s) {
+            this.$.selection.setItemSelected(s, false);
+          }, this);
+        } else {
+          this.$.selection.setItemSelected(this.selection, false);
+        }
+        this.selectedItem = null;
+        this.$.selection.clear();
+      },
+      valueToSelection: function(value) {
+        var item = (value === null || value === undefined) ?
+            null : this.items[this.valueToIndex(value)];
+        this.$.selection.select(item);
+      },
+      updateSelectedItem: function() {
+        this.selectedItem = this.selection;
+      },
+      selectedItemChanged: function() {
+        if (this.selectedItem) {
+          var t = this.selectedItem.templateInstance;
+          this.selectedModel = t ? t.model : undefined;
+        } else {
+          this.selectedModel = null;
+        }
+        this.selectedIndex = this.selectedItem ?
+            parseInt(this.valueToIndex(this.selected)) : -1;
+      },
+      valueToIndex: function(value) {
+        // find an item with value == value and return it's index
+        for (var i=0, items=this.items, c; (c=items[i]); i++) {
+          if (this.valueForNode(c) == value) {
+            return i;
+          }
+        }
+        // if no item found, the value itself is probably the index
+        return value;
+      },
+      valueForNode: function(node) {
+        return node[this.valueattr] || node.getAttribute(this.valueattr);
+      },
+      // events fired from <polymer-selection> object
+      selectionSelect: function(e, detail) {
+        this.updateSelectedItem();
+        if (detail.item) {
+          this.applySelection(detail.item, detail.isSelected)
+        }
+      },
+      applySelection: function(item, isSelected) {
+        if (this.selectedClass) {
+          item.classList.toggle(this.selectedClass, isSelected);
+        }
+        if (this.selectedProperty) {
+          item[this.selectedProperty] = isSelected;
+        }
+      },
+      // event fired from host
+      activateHandler: function(e) {
+        if (!this.notap) {
+          var i = this.findDistributedTarget(e.target, this.items);
+          if (i >= 0) {
+            var item = this.items[i];
+            var s = this.valueForNode(item) || i;
+            if (this.multi) {
+              if (this.selected) {
+                this.addRemoveSelected(s);
+              } else {
+                this.selected = [s];
+              }
+            } else {
+              this.selected = s;
+            }
+            this.asyncFire('polymer-activate', {item: item});
+          }
+        }
+      },
+      addRemoveSelected: function(value) {
+        var i = this.selected.indexOf(value);
+        if (i >= 0) {
+          this.selected.splice(i, 1);
+        } else {
+          this.selected.push(value);
+        }
+        this.valueToSelection(value);
+      },
+      findDistributedTarget: function(target, nodes) {
+        // find first ancestor of target (including itself) that
+        // is in nodes, if any
+        while (target && target != this) {
+          var i = Array.prototype.indexOf.call(nodes, target);
+          if (i >= 0) {
+            return i;
+          }
+          target = target.parentNode;
+        }
+      }
+    });
+  </script>
+</polymer-element>