BaseFieldDefinition::setDefaultValue

public BaseFieldDefinition::setDefaultValue($value)

public function setDefaultValue($value) {
  if ($value === NULL) {
    $value = [];
  }
  // Unless the value is an empty array, we may need to transform it.
  if (!is_array($value) || !empty($value)) {
    if (!is_array($value)) {
      $value = array(array($this->getMainPropertyName() => $value));
    }
    elseif (is_array($value) && !is_numeric(array_keys($value) [0])) {
      $value = array(0 => $value);
    }
  }
  $this->definition['default_value'] = $value;
  return $this;
}