code: function _objectToRDF(item) {
    var object = {};
  
    // convert value object to RDF
    if(_isValue(item)) {
      object.type = 'literal';
      var value = item['@value'];
      var datatype = item['@type'] || null;
  
      // convert to XSD datatypes as appropriate
      if(_isBoolean(value)) {
        object.value = value.toString();
        object.datatype = datatype || XSD_BOOLEAN;
      }
      else if(_isDouble(value) || datatype === XSD_DOUBLE) {
        // canonical double representation
        object.value = value.toExponential(15).replace(/(\d)0*e\+?/, '$1E');
        object.datatype = datatype || XSD_DOUBLE;
      }
      else if(_isNumber(value)) {
        object.value = value.toFixed(0);
        object.datatype = datatype || XSD_INTEGER;
      }
      else if('@language' in item) {
        object.value = value;
        object.datatype = datatype || RDF_LANGSTRING;
        object.language = item['@language'];
      }
      else {
        object.value = value;
        object.datatype = datatype || XSD_STRING;
      }
    }
    // convert string/node object to RDF
    else {
      var id = _isObject(item) ? item['@id'] : item;
      object.type = (id.indexOf('_:') === 0) ? 'blank node' : 'IRI';
      object.value = id;
    }
  
    return object;
  }
docs: Converts a JSON-LD value object to an RDF literal or a JSON-LD string or
  node object to an RDF resource.
  
  @param item the JSON-LD value or node object.
  
  @return the RDF literal or RDF resource.