backbone.projections/capped.js

Various projections for Backbone.Collection

// Generated by CoffeeScript 1.6.2
var Collection, extend, inducedOrdering, toArray, _ref,
  __hasProp = {}.hasOwnProperty,
  __extends = 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; };

Collection = ((typeof window !== "undefined" && window !== null ? window.Backbone : void 0) || require('backbone')).Collection;

_ref = (typeof window !== "undefined" && window !== null ? window._ : void 0) || require('underscore'), toArray = _ref.toArray, extend = _ref.extend;

inducedOrdering = function(collection) {
  var func;

  func = function(model) {
    return collection.indexOf(model);
  };
  func.induced = true;
  return func;
};

exports.Capped = (function(_super) {
  __extends(Capped, _super);

  function Capped(underlying, options) {
    var _this = this;

    if (options == null) {
      options = {};
    }
    this.underlying = underlying;
    this.model = underlying.model;
    this.comparator = options.comparator || inducedOrdering(underlying);
    this.options = extend({
      cap: 5
    }, underlying.options, options);
    Capped.__super__.constructor.call(this, this._capped(this.underlying.models), options);
    this.listenTo(this.underlying, {
      reset: function() {
        return _this.reset(_this._capped(_this.underlying.models));
      },
      remove: function(model) {
        var capped;

        if (_this.contains(model)) {
          _this.remove(model);
          capped = _this._capped(_this.underlying.models);
          return _this.add(capped[_this.options.cap - 1]);
        }
      },
      add: function(model) {
        if (_this.length < _this.options.cap) {
          return _this.add(model);
        } else if (_this.comparator(model) < _this.comparator(_this.last())) {
          _this.add(model);
          return _this.remove(_this.at(_this.options.cap));
        }
      },
      sort: function() {
        if (_this.comparator.induced) {
          return _this.reset(_this._capped(_this.underlying.models));
        }
      }
    });
  }

  Capped.prototype._capped = function(models) {
    var _this = this;

    models = toArray(models);
    models.sort(function(a, b) {
      a = _this.comparator(a);
      b = _this.comparator(b);
      if (a > b) {
        return 1;
      } else if (a < b) {
        return -1;
      } else {
        return 0;
      }
    });
    return models.slice(0, this.options.cap);
  };

  Capped.prototype.resize = function(cap) {
    var capped, idx, model, _i, _ref1;

    if (this.options.cap > cap) {
      this.options.cap = cap;
      _ref1 = this.models;
      for (idx = _i = _ref1.length - 1; _i >= 0; idx = _i += -1) {
        model = _ref1[idx];
        if (idx < cap) {
          break;
        }
        this.remove(model);
      }
    } else if (this.options.cap < cap) {
      this.options.cap = cap;
      capped = this._capped(this.underlying.models);
      this.add(capped.slice(this.length, this.options.cap));
    }
    return this.trigger('resize');
  };

  return Capped;

})(Collection);

exports.CappedCollection = exports.Capped;