Query conditionals

• is_404()
• is_archive()
• is_attachment() — opt $attachment
• is_author() — opt $author
• is_category() — opt $category
• is_comment_feed()
• is_comments_popup() — Deprecated since 4.5.0
• is_date()
• is_day()
• is_embed()
• is_feed() — opt $feed
• is_front_page()
• is_home()
• is_main_query()
• is_month()
• is_page() — opt $page
• is_paged()
• is_post_type_archive() — opt $type
• is_preview()
• is_robots()
• is_search()
• is_single() — opt $post
• is_singular() — opt $type
• is_tag() — opt $tag
• is_tax() — opt $taxonomy, opt $term
• is_time()
• is_trackback()
• is_year()

Other conditionals

• comments_open() — $post
• current_theme_supports() — $feature
• current_user_can() — $capability
• email_exists() — $email
• has_action() — $tag, opt $function
• has_category() — opt $category, opt $post
• has_filter() — $tag, opt $function
• has_post_thumbnail() — opt $post
• has_term() — opt $term, opt $taxonomy, opt $post
• in_category() — $category, opt $post
• in_the_loop()
• is_active_sidebar() — $index
• is_active_widget() — opt $callback, opt $widget, opt $base, opt $skip_inactive
• is_admin()
• is_admin_bar_showing()
• is_blog_admin()
• is_blog_installed()
• is_child_theme()
• is_customize_preview()
• is_dynamic_sidebar()
• is_local_attachment() — $url
• is_main_query()
• is_main_site() — opt $site, opt $network
• is_multisite()
• is_network_admin()
• is_new_day()
• is_page_template() — opt $template
• is_plugin_active() — $path
• is_plugin_active_for_network() — $path
• is_plugin_inactive() — $path
• is_plugin_page() — Deprecated since 3.1.0
• is_post_type_hierarchical() — $type
• is_rtl()
• is_serialized() — $data, opt $strict
• is_ssl()
• is_sticky() — opt $post
• is_super_admin() — opt $user
• is_taxonomy_hierarchical() — $taxonomy
• is_user_admin()
• is_user_logged_in()
• pings_open() — opt $post
• post_exists() — $title, opt $content, opt $date
• post_type_exists() — $type
• taxonomy_exists() — $taxonomy
• term_exists() — $term, opt $taxonomy, opt $parent
• username_exists() — $username
• wp_attachment_is_image() — opt $post
• wp_script_is() — $handle, opt $list