Put bootstrap in a function to keep variables out of global space

bootstrap.php

@@ -9,51 +9,63 @@
  * @link      http://webdevstudios.com
  */
 
-if ( is_admin() ) {
-	/**
-	 * Fires on the admin side when CMB2 is included/loaded.
-	 *
-	 * In most cases, this should be used to add metaboxes. See example-functions.php
-	 */
-	do_action( 'cmb2_admin_init' );
-}
-
 /**
- * Fires when CMB2 is included/loaded
- *
- * Can be used to add metaboxes if needed on the front-end or needed on the front and backend.
+ * Function to encapsulate the CMB2 bootstrap process.
+ * @since  2.1.3
+ * @return void
  */
-do_action( 'cmb2_init' );
+function cmb2_bootstrap() {
 
-/**
- * For back-compat. Does the dirtywork of instantiating all the
- * CMB2 instances for the cmb2_meta_boxes filter
- * @since  2.0.2
- */
-$all_meta_boxes_config = apply_filters( 'cmb2_meta_boxes', array() );
-foreach ( (array) $all_meta_boxes_config as $meta_box_config ) {
-	new CMB2( $meta_box_config );
-}
+	if ( is_admin() ) {
+		/**
+		 * Fires on the admin side when CMB2 is included/loaded.
+		 *
+		 * In most cases, this should be used to add metaboxes. See example-functions.php
+		 */
+		do_action( 'cmb2_admin_init' );
 
-/**
- * Fires after all CMB2 instances are created
- */
-do_action( 'cmb2_init_before_hookup' );
+	} else {
+		/**
+		 * Fires when CMB2 is included/loaded
+		 *
+		 * Can be used to add metaboxes if needed on the front-end (or the front and backend).
+		 */
+		do_action( 'cmb2_init' );
+	}
 
-/**
- * Get all created metaboxes, and instantiate CMB2_hookup
- * on metaboxes which require it.
- * @since  2.0.2
- */
-foreach ( CMB2_Boxes::get_all() as $cmb ) {
-	if ( $cmb->prop( 'hookup' ) ) {
-		$hookup = new CMB2_hookup( $cmb );
+	/**
+	 * For back-compat. Does the dirty-work of instantiating all the
+	 * CMB2 instances for the cmb2_meta_boxes filter
+	 * @since  2.0.2
+	 */
+	$cmb_config_arrays = apply_filters( 'cmb2_meta_boxes', array() );
+	foreach ( (array) $cmb_config_arrays as $cmb_config ) {
+		new CMB2( $cmb_config );
 	}
-}
 
-/**
- * Fires after CMB2 initiation process has been completed
- */
-do_action( 'cmb2_after_init' );
+	/**
+	 * Fires after all CMB2 instances are created
+	 */
+	do_action( 'cmb2_init_before_hookup' );
+
+	/**
+	 * Get all created metaboxes, and instantiate CMB2_hookup
+	 * on metaboxes which require it.
+	 * @since  2.0.2
+	 */
+	foreach ( CMB2_Boxes::get_all() as $cmb ) {
+		if ( $cmb->prop( 'hookup' ) ) {
+			$hookup = new CMB2_hookup( $cmb );
+		}
+		if ( $cmb->prop( 'show_in_rest' ) ) {
+			add_action( 'rest_api_init', array( new CMB2_REST( $cmb ), 'register_fields' ) );
+		}
+	}
+
+	/**
+	 * Fires after CMB2 initiation process has been completed
+	 */
+	do_action( 'cmb2_after_init' );
+}
 
 // End. That's it, folks! //

init.php

@@ -148,6 +148,7 @@ public function include_cmb() {
 
 			// Kick the whole thing off
 			require_once 'bootstrap.php';
+			cmb2_bootstrap();
 		}
 
 		/**