WordPress at a glance
function is not described

Automattic\WooCommerce\Admin

PluginsHelper::is_plugin_installed() public WC 1.0

Checks if a plugin is installed.

{} It's a method of the class: PluginsHelper{}

No Hooks.

Return

true|false. Nothing.

Usage

$result = PluginsHelper::is_plugin_installed( $plugin );
$plugin(string) (required)
Path to the plugin file relative to the plugins directory or the plugin directory name.

Code of PluginsHelper::is_plugin_installed() WC 5.3.0

<?php
public static function is_plugin_installed( $plugin ) {
	$plugin_path = self::get_plugin_path_from_slug( $plugin );
	return $plugin_path ? array_key_exists( $plugin_path, get_plugins() ) : false;
}