<?php // Disables form submission when pressing Enter, unless user has tabbed to a form button.
add_action( 'gform_pre_render', function ( $form ) { ?>

   <script type="text/javascript">
      jQuery(document).bind('gform_post_render', function() {
         jQuery(document).on( 'keypress', '.gform_wrapper', function (e) {
            var code = e.keyCode || e.which;
            if ( code == 13 && ! jQuery( e.target ).is( 'textarea,input[type="submit"],input[type="button"]' ) ) {
               e.preventDefault();
               return false;
            }
         });
      });
   </script>

   <?php return $form;

} );

#

Format your email field(s) in notifications as {usernames:user1:user2}{emails:account@example.com} or {usernames:user1:user2:user3} or as usual.

// Allow Gravity Form notification email fields to use usernames and email
// Format your email fields in notifications as {usernames:user1:user2:user3} or {usernames:user1:user2}{emails:account@example.com}
add_filter( 'gform_notification', function ( $notification, $form, $entry ) {

   // run all email fields in the notification through route translation
   if ( $notification['toType'] == 'email' ) {

      $notification['to'] = typewheel_gform_notification_translate_routes( $notification['to'] );

   } else if ( $notification['toType'] == 'routing' ) {

      foreach ( $notification['routing'] as $key => $route )
         $notification['routing'][ $key ]['email'] = typewheel_gform_notification_translate_routes( $notification['routing'][ $key ]['email'] );

   }

   $notification['from'] = typewheel_gform_notification_translate_routes( $notification['from'] );
   $notification['replyTo'] = typewheel_gform_notification_translate_routes( $notification['replyTo'] );
   $notification['bcc'] = typewheel_gform_notification_translate_routes( $notification['bcc'] );

   return $notification;

}, 10, 3 );

// reusable function for translating routes
function typewheel_gform_notification_translate_routes( $routes ) {

   if ( strpos( $routes, '{usernames' ) !== false || strpos( $routes, '{emails' ) !== false ) {

      // parse the username and email batches
      $routes = str_replace( array( '} {', '},{' ), '}{', $routes );
      $batches = explode( '}{', substr( $routes, 1, -1 ) );

      foreach ( $batches as $key => $batch ) {

         if ( strpos( $batch, 'usernames' ) !== false )
            $usernames = explode( ':', $batch );

         if ( strpos( $batch, 'emails' ) !== false )
            $emails = explode( ':', $batch );

      }

      $to = array(); // initialize the to array

      // loop through users and grab the email
      if ( isset( $usernames ) ) {
         unset( $usernames[0] );
         foreach ( $usernames as $username ) {
            $user = get_user_by( 'login', $username );
            if ( $user !== false ) $to[] = $user->user_email;
         }
      }

      // loop through the email addresses
      if ( isset( $emails ) ) {
         unset( $emails[0] );
         foreach ( $emails as $email ) $to[] = $email;
      }

      // add all addresses to the notification
      $routes = implode( ',', $to );

   }

   return $routes;

} // end typewheel_gform_notification_translate_routes()

#

@replace @int {{days}}

// Overrides the number of days until incomplete submissions (from Save & Continue) are purged
add_filter( 'gform_incomplete_submissions_expiration_days', function ( $expiration_days ) {
    return {{days}};
} );

Source

Optionally @replace .entry-content, <!-- START CONTRACT -->, <!-- END CONTRACT -->

// Send all HTML content between contentStart and contentEnd comments into Gravity Form paragraph text field with class of `content_receiver`
<script>
   jQuery(document).ready(function(){
      const contentStart = '<!-- START CONTRACT -->';
      const contentEnd = '<!-- END CONTRACT -->';
      const contentFull = jQuery('.entry-content').html();
      const contentSent = contentFull.substr(0,contentFull.indexOf(contentEnd)).substr(contentFull.indexOf(contentStart)).replace(contentStart,'');
      jQuery('.content_receiver textarea').val(contentSent.replace(/\n/gm,' '));
   });
</script>

Source

@replace {{_formID}}

<?php // Prepends or appends fields (marked by class `prepend-to-pages` or `append-to-pages` respectively) to every page of a Gravity Form
add_action( 'gform_pre_render{{_formID}}', function( $form ) {

   add_action( 'wp_footer', function () { ?>

      <script type="text/javascript">
         jQuery(document).bind('gform_post_render', function(event, form_id, current_page) {

            jQuery(jQuery('.gfield.prepend-to-pages').get().reverse()).each(function() {
               jQuery(this).prependTo(`#gform_page_${form_id}_${current_page} .gform_fields`);
            });

            jQuery(jQuery('.gfield.append-to-pages').get().reverse()).each(function() {
               jQuery(this).appendTo(`#gform_page_${form_id}_${current_page} .gform_fields`);
            });

         } );
      </script>

   <?php } );

   return $form;

} );

Source

// Provide an Account Handle input mask to receive Twitter and Instagram account handles
add_filter( 'gform_input_masks', function( $masks ) {

  $masks['Account Handle'] = '@*?**************************';
    return $masks;
  } );

add_filter( 'gform_input_mask_script', function( $script, $form_id, $field_id, $mask ) {

  if ( $mask == '@*?**************************' ) {
     $script = "jQuery.mask.definitions['*'] = '[A-Z,a-z,0-9,_]';   jQuery('#input_{$form_id}_{$field_id}').mask('" . esc_js( $mask ) . "',{placeholder:' '}).on('keypress', function(e){if(e.which == 13){jQuery(this).blur();}});";
  }

  return $script;

}, 10, 4 );

#