set: function()

in bower_modules/backbone/backbone.js [662:751]
69 lines of code
45 McCabe index (conditional complexity)

    set: function(models, options) {
      options = _.defaults({}, options, setOptions);
      if (options.parse) models = this.parse(models, options);
      var singular = !_.isArray(models);
      models = singular ? (models ? [models] : []) : _.clone(models);
      var i, l, id, model, attrs, existing, sort;
      var at = options.at;
      var targetModel = this.model;
      var sortable = this.comparator && (at == null) && options.sort !== false;
      var sortAttr = _.isString(this.comparator) ? this.comparator : null;
      var toAdd = [], toRemove = [], modelMap = {};
      var add = options.add, merge = options.merge, remove = options.remove;
      var order = !sortable && add && remove ? [] : false;

      // Turn bare objects into model references, and prevent invalid models
      // from being added.
      for (i = 0, l = models.length; i < l; i++) {
        attrs = models[i];
        if (attrs instanceof Model) {
          id = model = attrs;
        } else {
          id = attrs[targetModel.prototype.idAttribute];
        }

        // If a duplicate is found, prevent it from being added and
        // optionally merge it into the existing model.
        if (existing = this.get(id)) {
          if (remove) modelMap[existing.cid] = true;
          if (merge) {
            attrs = attrs === model ? model.attributes : attrs;
            if (options.parse) attrs = existing.parse(attrs, options);
            existing.set(attrs, options);
            if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
          }
          models[i] = existing;

        // If this is a new, valid model, push it to the `toAdd` list.
        } else if (add) {
          model = models[i] = this._prepareModel(attrs, options);
          if (!model) continue;
          toAdd.push(model);

          // Listen to added models' events, and index models for lookup by
          // `id` and by `cid`.
          model.on('all', this._onModelEvent, this);
          this._byId[model.cid] = model;
          if (model.id != null) this._byId[model.id] = model;
        }
        if (order) order.push(existing || model);
      }

      // Remove nonexistent models if appropriate.
      if (remove) {
        for (i = 0, l = this.length; i < l; ++i) {
          if (!modelMap[(model = this.models[i]).cid]) toRemove.push(model);
        }
        if (toRemove.length) this.remove(toRemove, options);
      }

      // See if sorting is needed, update `length` and splice in new models.
      if (toAdd.length || (order && order.length)) {
        if (sortable) sort = true;
        this.length += toAdd.length;
        if (at != null) {
          for (i = 0, l = toAdd.length; i < l; i++) {
            this.models.splice(at + i, 0, toAdd[i]);
          }
        } else {
          if (order) this.models.length = 0;
          var orderedModels = order || toAdd;
          for (i = 0, l = orderedModels.length; i < l; i++) {
            this.models.push(orderedModels[i]);
          }
        }
      }

      // Silently sort the collection if appropriate.
      if (sort) this.sort({silent: true});

      // Unless silenced, it's time to fire all appropriate add/sort events.
      if (!options.silent) {
        for (i = 0, l = toAdd.length; i < l; i++) {
          (model = toAdd[i]).trigger('add', model, this, options);
        }
        if (sort || (order && order.length)) this.trigger('sort', this, options);
      }
      
      // Return the added (or merged) model (or models).
      return singular ? models[0] : models;
    },