Conditional Love - Using WordPress Conditional Tags to Write More Effective Themes

Conditional Love
Using WordPress Conditional Tags to
Write More Eﬀective Themes
WordCamp Jacksonville 2016
@cwpnolen @emagineusa#wcjax

Who Am I?
Christian Nolen
Technical Director for emagine
WordPress Developer
@cwpnolen

We’re Hiring
http://www.emagine.com/careers/

All Developers  
are Lazy

@*#&-%*!

can be used in your Template files to
change what content is displayed and
how that content is displayed on a
particular page depending on what
conditions that page matches
CONDITIONAL TAGS

1. the state in which something exists
CONDITION
(kən-ˈdi-shən)
noun
2. a state of being

I JUST DROPPED IN
To See What Condition My Condition Was In
WordPress

Are You Hungry?

Are You Tired?

Are You Sad?

Are You Tired? 
or ( || ) 
Is it Morning?

Are You Drunk?
and (&&)
Do You Feel Sick?

allow you to ask one or many yes/no
(true/false) questions to WordPress
for the purpose of changing content,
presentation or functionality
CONDITIONAL TAGS

Template Hierarchy
https://developer.wordpress.org/themes/basics/template-hierarchy/

Title: About Us 
Slug: about-us 
Post ID: 28
Example Page

tmpl-about-us.php
page-about-us.php
page-28.php
page.php
singular.php
index.php

Why?

We don’t want this either

Consolidate your templates by  
major functional or design requirements

Common Usage

is_home()
is_front_page()

is_home() / is_front_page()
if ( is_home() ) :  
// Load blog listing template
get_template_part( 'partials', 'blog-posts' );  
endif;
if ( is_front_page() ) :  
// Load static home page stylesheet and javascript 
wp_enqueue_style( 'my-registered—home-css' );
wp_enqueue_script( 'my-registered—home-js' );  
endif;

is_category()
Parameters: Category ID, Name or Slug

is_category()
if ( is_category() ) :  
// Get Category Data
$category = get_category( get_query_var( 'cat' ) );  
endif;
<?php if ( is_category( 'web-development' ) ) : ?> 
<!—- A Geeky Image —->
<img src="http://goo.gl/8rqmrJ" alt="Nerd Image" />  
<php endif; ?>

is_active_sidebar()
Parameters: Name or ID
(required)

is_active_sidebar()
if ( is_active_sidebar( 'call-to-actions' ) ) :  
echo '<aside class="widgets">';
dynamic_sidebar( 'call-to-actions' ); 
echo '</aside>';  
endif;

is_single()
Parameters: Post ID, Title or Slug

is_single()
if ( is_single( '28' ) ) :  
// Awesome functionality  
// being conditionally loaded… poorly 
endif;

More Common Uses
has_post_thumbnail()
is_page()
is_admin()
has_excerpt()
is_author()
is_multisite()

Real World Applications

All Pages on Your Client Site
Landing Page

get_header( 'landing-page' );

is_page_template()
Parameter: Template Name

is_page_template()
if ( is_page_template( 'tmpl-landing-page.php' ) ) :  
// Get template partial for Landing Page header
get_template_part( 'partials', 'header-links-lp' ); 
else :
// Get default header links
get_template_part( 'partials', 'header-links-default' );
endif;

single-{post-type}-{slug}.php
single-{post-type}.php
single.php
singular.php
index.php

Posts
single-{post-type}-{slug}.php
single-{post-type}.php
single.php
singular.php
index.php
Pages
tmpl-about-us.php
page-about-us.php
page-28.php
page.php
singular.php
index.php

is_singular()
Parameter: Post Type Slug

is_singular()
if ( is_single() || is_page() || is_attachment() )
if ( is_singular() )
=

<article>
<?php
if ( is_singular( 'post' ) ) :
// Get blog date, author and categories 
get_template_part( 'partials/blog', 'meta' );
endif;
the_content();
?>
</article>
is_singular()

is_404()

while ( have_posts() ) : the_post();
the_content();
endwhile;
if ( is_404() ) :
// The page does not exist
echo 'This isn’t the page you’re looking for.’;
endif;
is_404()

Make Your Own  
Conditional Tag

function is_subpage() {
global $post;
if ( is_page() && $post->post_parent ) :
return true;
else :
return false;
endif;
}

Extend WordPress
Functionality

add_filter( 'body_class', 'add_body_classes' );
function add_body_classes( $classes ) {
return $classes;
}
if ( !is_front_page() )
$classes[] = 'interior';
if ( is_active_sidebar( 'call-to-actions' )
$classes[] = 'has-callouts';
if ( is_subpage() )
$classes[] = ‘is-subpage';

Additional Resources
• https://codex.wordpress.org/Conditional_Tags
• https://developer.wordpress.org/themes/basics/conditional-tags/
• http://code.tutsplus.com/articles/php-for-wordpress-mastering-
conditional-statements-and-tags--wp-22725
• https://docs.woothemes.com/document/conditional-tags/
• https://codex.bbpress.org/bbpress-conditional-tags/
• https://codex.buddypress.org/developer/template-tag-reference/
#is_-functions

Thank You
Christian Nolen
Technical Director for emagine
@cwpnolen

Conditional Love - Using WordPress Conditional Tags to Write More Effective Themes

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