simple configuration api usage Druapl 8(D8)

simple configuration api usage D8

# Taken from :https://www.drupal.org/developing/api/8/configuration/simple

//Immutable Config (Read Only)
$config = \Drupal::config('system.performance');

//Mutable Config (Read / Write)
$config = \Drupal::service('config.factory')->getEditable('system.performance');

// To read contents
$message = \Drupal::config('system.maintenance')->get('message'); //gets only particular key value, or array if data in next levels
$message = \Drupal::config('system.maintenance')->get();   // gets all config as array

// To Write data, first get mutable object, then write and then save. Config must be saved explicitly
// Set a scalar value.
$config->set('cache.page.enabled', 1);

// Set an array of values.
$page_cache_data = array('enabled' => 1, 'max_age' => 5);
$config->set('cache.page', $page_cache_data);

// Save your data to the file system.
$config->save();

// To clear, should be saved after clear
$config->clear(cache.page.enabled')->save();

// To delete entire set, donot save after delete
$config->delete(cache.page')->delete();