js/libs/ember-data.js
function(type) {
    var typeMaps = get(this, 'typeMaps'),
        guid = Ember.guidFor(type),
        typeMap;

    typeMap = typeMaps[guid];

    if (typeMap) { return typeMap; }

    typeMap = {
      idToRecord: {},
      records: [],
      metadata: {}
    };

    typeMaps[guid] = typeMap;

    return typeMap;
  }
function(type) {
    var typeMaps = get(this, 'typeMaps'),
        guid = Ember.guidFor(type),
        typeMap;

    typeMap = typeMaps[guid];

    if (typeMap) { return typeMap; }

    typeMap = {
      idToRecord: {},
      records: [],
      metadata: {}
    };

    typeMaps[guid] = typeMap;

    return typeMap;
  }
Returns a map of IDs to client IDs for a given type.

@method typeMapFor
@private
@param type
@return {Object} typeMap