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

the two-faced application library-framework

// Generated by CoffeeScript 1.12.2
(function() {
  var Base, SumFold, 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;

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

    function SumFold(list) {
      var i, len, ref, sum, x;
      SumFold.__super__.constructor.call(this);
      sum = 0;
      ref = list.list;
      for (i = 0, len = ref.length; i < len; i++) {
        x = ref[i];
        sum += x;
      }
      this._varying = new Varying(sum);
      this.listenTo(list, 'added', (function(_this) {
        return function(obj) {
          _this._varying.set(_this._varying.get() + (obj != null ? obj : 0));
        };
      })(this));
      this.listenTo(list, 'removed', (function(_this) {
        return function(obj) {
          _this._varying.set(_this._varying.get() - (obj != null ? obj : 0));
        };
      })(this));
    }

    SumFold.sum = function(list) {
      return Varying.managed((function() {
        return new SumFold(list, function(x, y) {
          return x < y;
        });
      }), function(incl) {
        return incl._varying;
      });
    };

    return SumFold;

  })(Base);

  module.exports = {
    SumFold: SumFold
  };

}).call(this);