2楼-- · 2019-01-11 01:17

Polymer element <iron-meta> is also an option. For me this was the easiest solution.

0人赞添加讨论(0) 举报

3楼-- · 2019-01-11 01:17

Sjmiles, one of Polymer's creators just posted the following snippet to the Polymer slack room as an example of shared data:

<!doctype html>
<html>
<head>

  <meta charset="utf-8">

  <meta name="description" content="shared-data element and repeats">

  <base href="http://milestech.net/components/">

  <script href="webcomponentsjs/webcomponents-lite.min.js"></script>
  <link href="polymer/polymer.html" rel="import">

</head>
<body>

  <demo-test></demo-test>

  <script>

    (function() {
      var private_data = [{name: 'a'}, {name: 'b'}, {name: 'c'}];
      Polymer({
        is: 'private-shared-data',
        properties: {
          data: {
            type: Object,
            notify: true,
            value: function() {
              return private_data;
            }
          }
        }
      });
    })();

    Polymer({
      is: 'xh-api-device',
      properties: {
        data: {
          type: Array,
          notify: true
        },
        _share: {
          value: document.createElement('private-shared-data')
        }
      },
      observers: [
        'dataChanged(data.*)'
      ],
      ready: function() {
        this.data = this._share.data;
        this.listen(this._share, 'data-changed', 'sharedDataChanged');
      },
      dataChanged: function(info) {
        this._share.fire('data-changed', info, {bubbles: false});
      },
      sharedDataChanged: function(e) {
        this.fire(e.type, e.detail);
      },
      add: function(name) {
        this.push('data', {name: name});
      }
    });

  </script>

  <dom-module id="demo-test">
    <template>

      <h2>One</h2>

      <xh-api-device id="devices" data="{{data}}"></xh-api-device>

      <template is="dom-repeat" items="{{data}}">
        <div>name: <span>{{item.name}}</span></div>
      </template>

      <h2>Two</h2>

      <xh-api-device data="{{data2}}"></xh-api-device>

      <template is="dom-repeat" items="{{data2}}">
        <div>name: <span>{{item.name}}</span></div>
      </template>

      <br>
      <br>

      <button on-click="populate">Populate</button>

    </template>
    <script>
      Polymer({
        populate: function() {
          this.$.devices.add((Math.random()*100).toFixed(2));
          // this works too
          //this.push('data', {name: (Math.random()*100).toFixed(2)});
        }
      });
    </script>
  </dom-module>

</body>
</html>

I've actually moved my app to using simple data binding, so I'm not sure of the validity of this approach, but maybe it would be useful to someone.

0人赞添加讨论(0) 举报

甜甜的少女心

4楼-- · 2019-01-11 01:19

I've extended Etherealones' solution to work as a Behavior, and to extend Polymers "set" and "notifyPath" methods to trigger the updates automatically. This is as close as i could get to a true databinding across components/elements:

globals-behavior.html:

<script>
var instances = [];
var dataGlobal = {};

var GlobalsBehaviour = {

  properties: {
    globals: {
      type: Object,
      notify: true,
      value: dataGlobal
    }
  },

  ready: function() {
    var _setOrig = this.set;
    var _notifyPathOrig = this.notifyPath;
    this.set = function() {
      _setOrig.apply(this, arguments);
      if (arguments[0].split(".")[0] === "globals") {
        this.invokeInstances(_notifyPathOrig, arguments);
      }
    };
    this.notifyPath = function(path, value) {
      _notifyPathOrig.apply(this, arguments);
      if (arguments[0].split(".")[0] === "globals") {
        this.invokeInstances(_notifyPathOrig, arguments);
      }
    };
  },

  invokeInstances: function(fn, args) {
    var i;
    for (i = 0; i < instances.length; i++) {
      instance = instances[i];
      if (instance !== this) {
        fn.apply(instance, args);
      }
    }
  },

  attached: function() {
    instances.push(this);
  },

  detached: function() {
    var i;
    i = instances.indexOf(this);
    if (i >= 0) {
      instances.splice(i, 1);
    }
  }
};

</script>

And in all polymer elements that should have access to the globals variable:

  <script>
    Polymer({
      is: 'globals-enabled-element',
      behaviors: [GlobalsBehaviour]
    });
  </script>

Examples:

I have posted a full example as a Gist on Github
Here's a snippet to see it in action:

    <!DOCTYPE html>
    <html>
      <head>
        <title>Globals Behavior Example</title>
        <link rel="import" href="//rawgit.com/Polymer/polymer/master/polymer.html">
        <dom-module id="globals-enabled-element">
          <template>
            <input type="text" value="{{globals.my_variable::input}}">
          </template>
          <script>
            var instances = [];
            var dataGlobal = {};
            
            var GlobalsBehaviour = {
              
              properties: {
                globals: {
                  type: Object,
                  notify: true,
                  value: dataGlobal
                }
              },
              
              ready: function() {
                var _setOrig = this.set;
                var _notifyPathOrig = this.notifyPath;
                this.set = function() {
                  _setOrig.apply(this, arguments);
                  if (arguments[0].split(".")[0] === "globals") {
                    this.invokeInstances(_notifyPathOrig, arguments);
                  }
                };
                this.notifyPath = function(path, value) {
                  _notifyPathOrig.apply(this, arguments);
                  if (arguments[0].split(".")[0] === "globals") {
                    this.invokeInstances(_notifyPathOrig, arguments);
                  }
                };
              },
              
              invokeInstances: function(fn, args) {
                var i;
                for (i = 0; i < instances.length; i++) {
                  instance = instances[i];
                  if (instance !== this) {
                    fn.apply(instance, args);
                  }
                }
              },
              
              attached: function() {
                instances.push(this);
              },
              
              detached: function() {
                var i;
                i = instances.indexOf(this);
                if (i >= 0) {
                  instances.splice(i, 1);
                }
              }
            };
          </script>
          <script>
            Polymer({
              is: 'globals-enabled-element',
              behaviors: [GlobalsBehaviour]
            });
          </script>
        </dom-module>
      </head>
      <body>
        <template is="dom-bind">
          <p>This is our first polymer element:</p>
          <globals-enabled-element id="element1"></globals-enabled-element>
          <p>And this is another one:</p>
          <globals-enabled-element id="element2"></globals-enabled-element>
        </template>
      </body>
    </html>

0人赞添加讨论(0) 举报

爷、活的狠高调

5楼-- · 2019-01-11 01:20

It is much easier to achieve the same effect of global variables if you wrapped your application in a template. Watch the explanation in this video (I linked to the exact minute and second where the concept is explained).

0人赞添加讨论(0) 举报

倾城　Initia

6楼-- · 2019-01-11 01:21

I've combined all suggestions above into the following global polymer object

<dom-module id="app-data">
</dom-module>
<script>
    (function () {
        var instances = [];
        var vars = Object.create(Polymer.Base);
        var commondata = {
            get loader() {
                return vars.get("loader");
            },
            set loader(v) {
                return setGlob("loader", v);
            }
        };

        function setGlob(path, v) {
            if (vars.get(path) != v) {
                vars.set(path, v);
                for (var i = 0; i < instances.length; i++) {
                    instances[i].notifyPath("data." + path, v);
                }
            }
            return v;
        }

        Polymer({
            is: 'app-data',
            properties: {
                data: {
                    type: Object,
                    value: commondata,
                    notify: true,
                    readonly: true
                }
            },
            created: function () {
                instances.push(this);
            },

            detached: function () {
                var i = instances.indexOf(this);
                if (i >= 0) {
                    instances.splice(i, 1);
                }
            }
        });
    })();
</script>

and use it elsewere like

<dom-module id="app-navigation">
    <style>

    </style>
    <template>
        <app-data id="data01" data="{{data1}}" ></app-data>
        <app-data id="data02" data="{{data2}}"></app-data>
        <span>{{data1.loader}}</span>
        <span>{{data2.loader}}</span>
    </template>

</dom-module>
<script>

    (function () {
        Polymer({
            is: 'app-navigation',
            properties: {
            },
            ready: function () {
                this.data1.loader=51;
            }
        });
    })();
</script>

Changing either data1.loader or data2.loader affects other instances. You should to extend commondata object to add more global properties like it shown with loader property.

0人赞添加讨论(0) 举报

Root（大扎）

7楼-- · 2019-01-11 01:22

I have implemented a pattern like iron-signals uses for this purpose. So the basic principle is that you manually notify other instances when an update occurs.

Consider this:

<dom-module id="x-global">
<script>
(function() {
  var instances = [];

  var dataGlobal = {};

  Polymer({
    is: 'x-global',

    properties: {
      data: {
        type: Object,
        value: dataGlobal,
      },
    },

    attached: function() {
      instances.push(this);
    },

    detached: function() {
      var i = instances.indexOf(this);
      if (i >= 0) {
        instances.splice(i, 1);
      }
    },

    set_: function(path, value) {
      this.set(path, value);

      instances.forEach(function(instance) {
        if (instance !== this) { // if it is not this one
          instance.notifyPath(path, value);
        }
      }.bind(this));
    },

    notifyPath_: function(path, value) {
      instances.forEach(function(instance) {
        instance.notifyPath(path, value);
      });
    },

    fire_: function(name, d) {
      instances.forEach(function(instance) {
        instance.fire(name, d);
      });
    },
  });
})();
</script>
</dom-module>

You will simple call the version that have an underscore suffix like fire_ when you are firing an event. You can even create a Polymer Behavior of some sort with this pattern I guess.

Beware that preceding underscore properties are already used by Polymer so don't go ahead and convert these to _fire.

P.S.: I didn't look around to solve how to reflect the notification of this.push(array, value); as I don't need it. I don't know if it's possible this way. Should go find Polymer.Base.push.

0人赞添加讨论(0) 举报

Polymer 1.0 Global Variables

Examples:

采纳回答

编辑标签

举报内容

检举类型

检举原因

检举说明(必填)

打开微信“扫一扫”，打开网页后点击屏幕右上角分享按钮

付费偷看金额在0.1-10元之间