Pass boolean value in shortcode

3 comments

1. Is easy to use 0 and 1 values and then typecasting inside the function:

   [shortcode boolean_attribute='1'] or [shortcode boolean_attribute='0']

   but if you want you can also strictly check for 'false' and assign it to boolean, in this way you can also use:

   [shortcode boolean_attribute='false'] or [shortcode boolean_attribute='true']

   Then:

   add_shortcode( 'shortcode', 'shortcode_cb' );
   
   function shortcode_cb( $atts ) {
     extract( shortcode_atts( array(
       'boolean_attribute' => 1
     ), $atts ) );
     if ( $boolean_attribute === 'false' ) $boolean_attribute = false; // just to be sure...
     $boolean_attribute = (bool) $boolean_attribute;
   }
   

2. As an extension to @G.M. answer (which is the only possible way to do this), here’s a slightly shortened/beautified and and an extended version (which I personally prefer):

   Shortened/Beautified variant

   It’s enough to do a boolean check for the contained value. If it’s true, the result will be (bool) true, else it will be false. This produces a one case true, everything else false result.

   add_shortcode( 'shortcodeWPSE', 'wpse119294ShortcodeCbA' );
   function wpse119294ShortcodeCbA( $atts ) {
       $args = shortcode_atts( array(
           'boolAttr' => 'true'
       ), $atts, 'shortcodeWPSE' );
   
       $args['boolAttr'] = 'true' === $args['boolAttr'];
   }
   

   Extended/User-safe variant

   The reason why I prefer this version is that it allows the user to type in on/yes/1 as an alias for true. This reduces the chance for user errors when the user doesn’t remember what the actual value for true was.

   add_shortcode( 'shortcodeWPSE', 'wpse119294ShortcodeCbA' );
   function wpse119294ShortcodeCbA( $atts ) {
       $args = shortcode_atts( array(
           'boolAttr' => 'true'
       ), $atts, 'shortcodeWPSE' );
   
       $args['boolAttr'] = filter_var( $args['boolAttr'], FILTER_VALIDATE_BOOLEAN );
   }
   

   Additional notes:

   1) Always pass the 3rd argument for shortcode_atts(). Else the shortcode attributes filter is impossible to target.

   // The var in the filter name refers to the 3rd argument.
   apply_filters( "shortcode_atts_{$shortcode}", $out, $pairs, $atts );
   

   2) Never use extract(). Even core wants to reduce those calls. It’s equally worse to global variables, as IDEs don’t stand a chance to resolve the extracted contents and will throw failure messages.

3. Here a shorter simple version, building on gmazzap’s answer:

   Use ‘1’ or ‘0’, then cast using a double bang “!!” which changes a “truthy/falsey” value to it’s boolean equivalent

   note this will NOT work with “true” and “false” strings, only “1” and “0”

   [myshortcode myvar="0"]
   
   myshortcodefunction( $args )
   {
      $myvar = !! $args['myvar'];
      var_dump($myvar); // prints bool(false)
   }
   

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