Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like Jetpack_Memberships often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Jetpack_Memberships, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 15 | class Jetpack_Memberships { | 
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| 16 | /**  | 
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| 17 | * CSS class prefix to use in the styling.  | 
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| 18 | *  | 
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| 19 | * @var string  | 
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| 20 | */  | 
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| 21 | public static $css_classname_prefix = 'jetpack-memberships';  | 
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| 22 | /**  | 
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| 23 | * Our CPT type for the product (plan).  | 
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| 24 | *  | 
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| 25 | * @var string  | 
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| 26 | */  | 
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| 27 | public static $post_type_plan = 'jp_mem_plan';  | 
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| 28 | /**  | 
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| 29 | * Option that will store currently set up account (Stripe etc) id for memberships.  | 
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| 30 | *  | 
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| 31 | * @var string  | 
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| 32 | */  | 
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| 33 | public static $connected_account_id_option_name = 'jetpack-memberships-connected-account-id';  | 
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| 34 | /**  | 
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| 35 | * Button block type to use.  | 
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| 36 | *  | 
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| 37 | * @var string  | 
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| 38 | */  | 
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| 39 | private static $button_block_name = 'recurring-payments';  | 
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| 40 | |||
| 41 | /**  | 
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| 42 | * These are defaults for wp_kses ran on the membership button.  | 
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| 43 | *  | 
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| 44 | * @var array  | 
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| 45 | */  | 
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| 46 | private static $tags_allowed_in_the_button = array( 'br' => array() );  | 
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| 47 | |||
| 48 | /**  | 
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| 49 | * The minimum required plan for this Gutenberg block.  | 
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| 50 | *  | 
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| 51 | * @var string Plan slug  | 
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| 52 | */  | 
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| 53 | private static $required_plan;  | 
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| 54 | |||
| 55 | /**  | 
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| 56 | * Track recurring payments block registration.  | 
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| 57 | *  | 
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| 58 | * @var boolean True if block registration has been executed.  | 
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| 59 | */  | 
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| 60 | private static $has_registered_block = false;  | 
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| 61 | |||
| 62 | /**  | 
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| 63 | * Classic singleton pattern  | 
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| 64 | *  | 
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| 65 | * @var Jetpack_Memberships  | 
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| 66 | */  | 
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| 67 | private static $instance;  | 
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| 68 | |||
| 69 | /**  | 
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| 70 | * Currencies we support and Stripe's minimum amount for a transaction in that currency.  | 
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| 71 | *  | 
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| 72 | * @link https://stripe.com/docs/currencies#minimum-and-maximum-charge-amounts  | 
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| 73 | *  | 
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| 74 | * List has to be in with `SUPPORTED_CURRENCIES` in extensions/shared/currencies.js and  | 
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| 75 | * `Memberships_Product::SUPPORTED_CURRENCIES` in the WP.com memberships library.  | 
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| 76 | */  | 
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| 77 | const SUPPORTED_CURRENCIES = array(  | 
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| 78 | 'USD' => 0.5,  | 
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| 79 | 'AUD' => 0.5,  | 
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| 80 | 'BRL' => 0.5,  | 
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| 81 | 'CAD' => 0.5,  | 
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| 82 | 'CHF' => 0.5,  | 
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| 83 | 'DKK' => 2.5,  | 
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| 84 | 'EUR' => 0.5,  | 
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| 85 | 'GBP' => 0.3,  | 
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| 86 | 'HKD' => 4.0,  | 
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| 87 | 'INR' => 0.5,  | 
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| 88 | 'JPY' => 50,  | 
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| 89 | 'MXN' => 10,  | 
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| 90 | 'NOK' => 3.0,  | 
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| 91 | 'NZD' => 0.5,  | 
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| 92 | 'PLN' => 2.0,  | 
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| 93 | 'SEK' => 3.0,  | 
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| 94 | 'SGD' => 0.5,  | 
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| 95 | );  | 
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| 96 | |||
| 97 | /**  | 
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| 98 | * Jetpack_Memberships constructor.  | 
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| 99 | */  | 
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| 100 | 	private function __construct() {} | 
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| 101 | |||
| 102 | /**  | 
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| 103 | * The actual constructor initializing the object.  | 
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| 104 | *  | 
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| 105 | * @return Jetpack_Memberships  | 
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| 106 | */  | 
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| 107 | View Code Duplication | 	public static function get_instance() { | 
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| 117 | /**  | 
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| 118 | * Get the map that defines the shape of CPT post. keys are names of fields and  | 
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| 119 | * 'meta' is the name of actual WP post meta field that corresponds.  | 
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| 120 | *  | 
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| 121 | * @return array  | 
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| 122 | */  | 
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| 123 | 	private static function get_plan_property_mapping() { | 
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| 135 | |||
| 136 | /**  | 
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| 137 | * Inits further hooks on init hook.  | 
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| 138 | */  | 
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| 139 | 	private function register_init_hook() { | 
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| 143 | |||
| 144 | /**  | 
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| 145 | * Actual hooks initializing on init.  | 
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| 146 | */  | 
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| 147 | 	public function init_hook_action() { | 
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| 152 | |||
| 153 | /**  | 
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| 154 | * Sets up the custom post types for the module.  | 
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| 155 | */  | 
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| 156 | 	private function setup_cpts() { | 
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| 189 | |||
| 190 | /**  | 
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| 191 | * Allows custom post types to be used by REST API.  | 
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| 192 | *  | 
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| 193 | * @param array $post_types - other post types.  | 
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| 194 | *  | 
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| 195 | * @see hook 'rest_api_allowed_post_types'  | 
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| 196 | * @return array  | 
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| 197 | */  | 
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| 198 | 	public function allow_rest_api_types( $post_types ) { | 
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| 203 | |||
| 204 | /**  | 
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| 205 | * Allows custom meta fields to sync.  | 
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| 206 | *  | 
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| 207 | * @param array $post_meta - previously changet post meta.  | 
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| 208 | *  | 
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| 209 | * @return array  | 
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| 210 | */  | 
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| 211 | 	public function allow_sync_post_meta( $post_meta ) { | 
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| 218 | |||
| 219 | /**  | 
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| 220 | * This returns meta attribute of passet array.  | 
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| 221 | * Used for array functions.  | 
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| 222 | *  | 
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| 223 | * @param array $map - stuff.  | 
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| 224 | *  | 
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| 225 | * @return mixed  | 
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| 226 | */  | 
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| 227 | 	public function return_meta( $map ) { | 
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| 230 | |||
| 231 | /**  | 
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| 232 | * Renders a preview of the Recurring Payment button, which is not hooked  | 
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| 233 | * up to the subscription url. Used to preview the block on the frontend  | 
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| 234 | * for site editors when Stripe has not been connected.  | 
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| 235 | *  | 
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| 236 | * @param array $attrs - attributes in the shortcode.  | 
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| 237 | * @param string $content - Recurring Payment block content.  | 
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                         | 
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| 238 | *  | 
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| 239 | * @return string|void  | 
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| 240 | */  | 
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| 241 | 	public function render_button_preview( $attrs, $content = null ) { | 
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| 249 | |||
| 250 | /**  | 
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| 251 | * Determines whether the button preview should be rendered. Returns true  | 
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| 252 | * if the user has editing permissions, the button is not configured correctly  | 
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| 253 | * (because it requires a plan upgrade or Stripe connection), and the  | 
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| 254 | * button is a child of a Premium Content block.  | 
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| 255 | *  | 
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| 256 | * @param WP_Block $block Recurring Payments block instance.  | 
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| 257 | *  | 
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| 258 | * @return boolean  | 
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| 259 | */  | 
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| 260 | 	public function should_render_button_preview( $block ) { | 
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| 277 | |||
| 278 | /**  | 
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| 279 | * Callback that parses the membership purchase shortcode.  | 
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| 280 | *  | 
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| 281 | * @param array $attributes - attributes in the shortcode. `id` here is the CPT id of the plan.  | 
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| 282 | * @param string $content - Recurring Payment block content.  | 
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| 283 | * @param WP_Block $block - Recurring Payment block instance.  | 
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| 284 | *  | 
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| 285 | * @return string|void  | 
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| 286 | */  | 
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| 287 | 	public function render_button( $attributes, $content, $block ) { | 
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| 318 | |||
| 319 | /**  | 
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| 320 | * Builds subscription URL for this membership using the current blog and  | 
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| 321 | * supplied plan IDs.  | 
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| 322 | *  | 
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| 323 | * @param integer $plan_id - Unique ID for the plan being subscribed to.  | 
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| 324 | * @return string  | 
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| 325 | */  | 
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| 326 | 	public function get_subscription_url( $plan_id ) { | 
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| 340 | |||
| 341 | /**  | 
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| 342 | * Renders a deprecated legacy version of the button HTML.  | 
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| 343 | *  | 
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| 344 | * @param array $attrs - Array containing the Recurring Payment block attributes.  | 
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| 345 | * @param integer $plan_id - Unique plan ID the membership is for.  | 
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| 346 | *  | 
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| 347 | * @return string  | 
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| 348 | */  | 
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| 349 | 	public function deprecated_render_button_v1( $attrs, $plan_id ) { | 
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| 391 | |||
| 392 | /**  | 
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| 393 | * Get current blog id.  | 
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| 394 | *  | 
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| 395 | * @return int  | 
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| 396 | */  | 
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| 397 | 	public static function get_blog_id() { | 
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| 404 | |||
| 405 | /**  | 
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| 406 | * Get the id of the connected payment acount (Stripe etc).  | 
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| 407 | *  | 
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| 408 | * @return int|void  | 
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| 409 | */  | 
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| 410 | 	public static function get_connected_account_id() { | 
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| 413 | |||
| 414 | /**  | 
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| 415 | * Determines whether the current user can edit.  | 
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| 416 | *  | 
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| 417 | * @return bool Whether the user can edit.  | 
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| 418 | */  | 
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| 419 | 	public static function user_can_edit() { | 
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| 424 | |||
| 425 | /**  | 
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| 426 | * Whether Recurring Payments are enabled. True if the block  | 
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| 427 | * is supported by the site's plan, or if it is a Jetpack site  | 
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| 428 | * and the feature to enable upgrade nudges is active.  | 
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| 429 | *  | 
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| 430 | * @return bool  | 
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| 431 | */  | 
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| 432 | 	public static function is_enabled_jetpack_recurring_payments() { | 
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| 442 | |||
| 443 | /**  | 
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| 444 | * Whether the site's plan supports the Recurring Payments block.  | 
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| 445 | */  | 
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| 446 | 	public static function is_supported_jetpack_recurring_payments() { | 
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| 447 | // For WPCOM sites.  | 
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| 448 | 		if ( defined( 'IS_WPCOM' ) && IS_WPCOM && function_exists( 'has_any_blog_stickers' ) ) { | 
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| 449 | $site_id = get_current_blog_id();  | 
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| 450 | return has_any_blog_stickers( array( 'personal-plan', 'premium-plan', 'business-plan', 'ecommerce-plan' ), $site_id );  | 
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| 451 | }  | 
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| 452 | // For Jetpack sites.  | 
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| 453 | return (  | 
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| 454 | Jetpack::is_active() &&  | 
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| 455 | Jetpack_Plan::supports( 'recurring-payments' )  | 
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| 456 | );  | 
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| 457 | }  | 
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| 458 | |||
| 459 | /**  | 
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| 460 | * Register the Recurring Payments Gutenberg block  | 
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| 461 | */  | 
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| 462 | 	public function register_gutenberg_block() { | 
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| 493 | }  | 
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| 494 | Jetpack_Memberships::get_instance();  | 
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| 495 | 
This check looks for
@paramannotations where the type inferred by our type inference engine differs from the declared type.It makes a suggestion as to what type it considers more descriptive.
Most often this is a case of a parameter that can be null in addition to its declared types.