janus/lib/collection/derived/includes-fold.js

the two-faced application library-framework

// Generated by CoffeeScript 1.12.2
(function() {
  var Base, IncludesFold, Varying,
    extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
    hasProp = {}.hasOwnProperty;

  Varying = require('../../core/varying').Varying;

  Base = require('../../core/base').Base;

  IncludesFold = (function(superClass) {
    extend(IncludesFold, superClass);

    function IncludesFold(list, x) {
      IncludesFold.__super__.constructor.call(this);
      this._varying = new Varying(false);
      this.listenTo(list, 'added', (function(_this) {
        return function(obj) {
          if (obj === _this._value) {
            _this._count += 1;
            _this._varying.set(true);
          }
        };
      })(this));
      this.listenTo(list, 'removed', (function(_this) {
        return function(obj) {
          if (obj === _this._value) {
            _this._count -= 1;
            if (_this._count === 0) {
              _this._varying.set(false);
            }
          }
        };
      })(this));
      this.reactTo(Varying.of(x), (function(_this) {
        return function(value) {
          var i, len, ref;
          _this._value = value;
          _this._count = 0;
          ref = list.list;
          for (i = 0, len = ref.length; i < len; i++) {
            x = ref[i];
            if (x === value) {
              _this._count += 1;
            }
          }
          _this._varying.set(_this._count > 0);
        };
      })(this));
    }

    IncludesFold.includes = function(list, x) {
      return Varying.managed((function() {
        return new IncludesFold(list, x);
      }), function(incl) {
        return incl._varying;
      });
    };

    return IncludesFold;

  })(Base);

  module.exports = {
    IncludesFold: IncludesFold
  };

}).call(this);