appengine/ui/interval-timer.html

<!--
  Copyright 2016 The LUCI Authors. All rights reserved.
  Use of this source code is governed under the Apache License, Version 2.0
  that can be found in the LICENSE file.

  The interval-timer element fires the trigger event repeatedly using a
  configurable property.

  Properties:
    period - The number of seconds that should elapse before the trigger event fires.  After
      firing, the timer resets.  If the period is changed, the timer is also reset. -1 means to
      stop the timer.

  Methods:
    None.

  Events:
    trigger - The specified time has come to perform some event.  The event object will have the
      following attributes:
        period: Number, the period that was used to create the event.
-->
<dom-module id="interval-timer">
  <script>
  (function() {
    Polymer({
      is: "interval-timer",

      properties: {
        period: {
          type: Number,
          value: -1,  // by default, never fire.
          observer: "_periodChanged",
        },
      },

      _periodChanged: function(period) {
        if (this._timeout) {
          window.clearTimeout(this._timeout);
        }
        if (period > 0) {
          this._timeout = window.setTimeout(function() {
            this.fire('trigger');
            // refire event
            this._periodChanged(period);
          }.bind(this), period * 1000);
        }
      },
    });
  }());
  </script>
</dom-module>