public function getField($name)
    {
        if ($this->fields === null) {
            $this->getFields();
        }
        Utils::invariant(isset($this->fields[$name]), 'Field "%s" is not defined for type "%s"', $name, $this->name);

        return $this->fields[$name];
    }
public function getField($name)
    {
        if ($this->fields === null) {
            $this->getFields();
        }
        Utils::invariant(isset($this->fields[$name]), 'Field "%s" is not defined for type "%s"', $name, $this->name);

        return $this->fields[$name];
    }
@param string $name

@return FieldDefinition

@throws Exception