tuyakhov / yii2-json-api

            $fieldDefinitions = array_combine($vars, $vars);

        }

        foreach ($this->resolveFields($fieldDefinitions, $fields) as $name => $definition) {

            $attributes[$name] = is_string($definition) ? $this->$definition : call_user_func($definition, $this, $name);

        }

        return $attributes;

    }

            $fields = $this->extraFields();

        }

        foreach ($this->resolveFields($fields) as $name => $definition) {

            $relationships[$name] = is_string($definition) ? $this->$definition : call_user_func($definition, $this, $name);

        }

        return $relationships;

    }