slick.remotemodel-yahoo.ts

(function ($) {
  /***
   * A sample AJAX data store implementation.
   * Right now, it's hooked up to load Hackernews stories, but can
   * easily be extended to support any JSONP-compatible backend that accepts paging parameters.
   */
  function RemoteModel() {
    // private
    var PAGESIZE = 10;
    var data: { [key: number]: any; length: number } = { length: 0 };
    var h_request: number | null = null;
    var req: JsonpExtendedOptions | null = null; // ajax request

    // events
    var onDataLoading = new Slick.Event();
    var onDataLoaded = new Slick.Event();

    function init() {}

    function isDataLoaded(from: number, to: number) {
      for (var i = from; i <= to; i++) {
        if (data[i] == undefined || data[i] == null) {
          return false;
        }
      }

      return true;
    }

    function clear() {
      for (var key in data) {
        delete data[key];
      }
      data.length = 0;
    }

    function ensureData(from: number, to: number) {
      if (req) {
        req.abort();
        for (var i = req.fromPage; i <= req.toPage; i++) {
          data[i * PAGESIZE] = undefined;
        }
      }

      if (from < 0) {
        from = 0;
      }

      if (data.length > 0) {
        to = Math.min(to, data.length - 1);
      }

      var fromPage = Math.floor(from / PAGESIZE);
      var toPage = Math.floor(to / PAGESIZE);

      while (data[fromPage * PAGESIZE] !== undefined && fromPage < toPage)
        fromPage++;

      while (data[toPage * PAGESIZE] !== undefined && fromPage < toPage)
        toPage--;

      if (
        fromPage > toPage ||
        (fromPage == toPage && data[fromPage * PAGESIZE] !== undefined)
      ) {
        // TODO:  look-ahead
        onDataLoaded.notify({ from: from, to: to });
        return;
      }

      var recStart = fromPage * PAGESIZE;
      var recCount = (toPage - fromPage) * PAGESIZE + PAGESIZE;

      var url =
        "https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20rss" +
        "(" +
        recStart +
        "%2C" +
        recCount +
        ")" +
        "%20where%20url%3D%22http%3A%2F%2Frss.news.yahoo.com%2Frss%2Ftopstories%22" +
        "&format=json";

      if (h_request != null) {
        clearTimeout(h_request);
      }

      h_request = window.setTimeout(function () {
        for (var i = fromPage; i <= toPage; i++) data[i * PAGESIZE] = null; // null indicates a 'requested but not available yet'

        onDataLoading.notify({ from: from, to: to });

        req = $.jsonp({
          url: url,
          callbackParameter: "callback",
          cache: true,
          success: function (json) {
            onSuccess(json, recStart);
          },
          error: function () {
            onError(fromPage, toPage);
          },
        });

        req.fromPage = fromPage;
        req.toPage = toPage;
      }, 50);
    }

    function onError(fromPage: number, toPage: number) {
      alert("error loading pages " + fromPage + " to " + toPage);
    }

    // SAMPLE DATA
    //    {
    //      "query": {
    //        "count": 40,
    //        "created": "2015-03-03T00:34:00Z",
    //        "lang": "en-US",
    //        "results": {
    //          "item": [
    //            {
    //              "title": "Netanyahu assails Iran deal, touts US-Israel ties",
    //              "description": "<p><a href=\"http://news.yahoo.com/netanyahu-us-officials-face-off-iran-133539021--politics.html\"><img src=\"http://l2.yimg.com/bt/api/res/1.2/4eoBxbJStrbGAKbmBYOJfg--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTg2O3E9NzU7dz0xMzA-/http://media.zenfs.com/en_us/News/ap_webfeeds/2f3a20c2d46d9f096f0f6a706700d430.jpg\" width=\"130\" height=\"86\" alt=\"Israeli Prime Minister Benjamin Netanyahu addresses the 2015 American Israel Public Affairs Committee (AIPAC) Policy Conference in Washington, Monday, March 2, 2015. (AP Photo/Cliff Owen)\" align=\"left\" title=\"Israeli Prime Minister Benjamin Netanyahu addresses the 2015 American Israel Public Affairs Committee (AIPAC) Policy Conference in Washington, Monday, March 2, 2015. (AP Photo/Cliff Owen)\" border=\"0\" /></a>WASHINGTON (AP) — Seeking to lower tensions, Benjamin Netanyahu and U.S. officials cast their dispute over Iran as a family squabble on Monday, even as the Israeli leader claimed President Barack Obama did not — and could not — fully understand his nation&#039;s vital security concerns.</p><br clear=\"all\"/>",
    //              "link": "http://news.yahoo.com/netanyahu-us-officials-face-off-iran-133539021--politics.html",
    //              "pubDate": "Mon, 02 Mar 2015 19:17:36 -0500",
    //              "source": {
    //                "url": "http://www.ap.org/",
    //                "content": "Associated Press"
    //              },
    //              "guid": {
    //                "isPermaLink": "false",
    //                "content": "netanyahu-us-officials-face-off-iran-133539021--politics"
    //              },
    //              "content": {
    //                "height": "86",
    //                "type": "image/jpeg",
    //                "url": "http://l2.yimg.com/bt/api/res/1.2/4eoBxbJStrbGAKbmBYOJfg--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTg2O3E9NzU7dz0xMzA-/http://media.zenfs.com/en_us/News/ap_webfeeds/2f3a20c2d46d9f096f0f6a706700d430.jpg",
    //                "width": "130"
    //              },
    //              "text": {
    //                "type": "html",
    //                "content": "<p><a href=\"http://news.yahoo.com/netanyahu-us-officials-face-off-iran-133539021--politics.html\"><img src=\"http://l2.yimg.com/bt/api/res/1.2/4eoBxbJStrbGAKbmBYOJfg--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTg2O3E9NzU7dz0xMzA-/http://media.zenfs.com/en_us/News/ap_webfeeds/2f3a20c2d46d9f096f0f6a706700d430.jpg\" width=\"130\" height=\"86\" alt=\"Israeli Prime Minister Benjamin Netanyahu addresses the 2015 American Israel Public Affairs Committee (AIPAC) Policy Conference in Washington, Monday, March 2, 2015. (AP Photo/Cliff Owen)\" align=\"left\" title=\"Israeli Prime Minister Benjamin Netanyahu addresses the 2015 American Israel Public Affairs Committee (AIPAC) Policy Conference in Washington, Monday, March 2, 2015. (AP Photo/Cliff Owen)\" border=\"0\" /></a>WASHINGTON (AP) — Seeking to lower tensions, Benjamin Netanyahu and U.S. officials cast their dispute over Iran as a family squabble on Monday, even as the Israeli leader claimed President Barack Obama did not — and could not — fully understand his nation&#039;s vital security concerns.</p><br clear=\"all\"/>"
    //              },
    //              "credit": {
    //                "role": "publishing company"
    //              }
    //            },
    //            {... },
    //            {... },
    //          ]
    //        }
    //      }
    //    }

    function onSuccess(
      json: { query: { count: number; results: { item: any[] } } },
      recStart: number
    ) {
      var recEnd = recStart;
      if (json.query.count > 0) {
        var results = json.query.results.item;
        recEnd = recStart + results.length;
        data.length = 100; // Math.min(parseInt(results.length),1000); // limitation of the API

        for (var i = 0; i < results.length; i++) {
          var item = results[i];

          item.pubDate = new Date(item.pubDate);

          data[recStart + i] = { index: recStart + i };
          data[recStart + i].pubDate = item.pubDate;
          data[recStart + i].title = item.title;
          data[recStart + i].url = item.link;
          data[recStart + i].text = item.description;
        }
      }
      req = null;

      onDataLoaded.notify({ from: recStart, to: recEnd });
    }

    function reloadData(from: number, to: number) {
      for (var i = from; i <= to; i++) delete data[i];

      ensureData(from, to);
    }

    init();

    return {
      // properties
      data: data,

      // methods
      clear: clear,
      isDataLoaded: isDataLoaded,
      ensureData: ensureData,
      reloadData: reloadData,

      // events
      onDataLoading: onDataLoading,
      onDataLoaded: onDataLoaded,
    };
  }

  // exports
  $.extend(true, window, {
    Slick: {
      Data: {
        RemoteModel: RemoteModel,
      },
    },
  });
})(jQuery);