Topic
Step-by-step guides for getting things done in WordPress.
WordPress Tutorials
Deferring a script with this filter detaches it from the dependency order WordPress maintains, and any inline script attached to it runs before it loads. Core has had a strategy argument since 6.3 that handles both; the filter remains for what the argument cannot express.
WordPress Tutorials
The filter runs before the insert, which is what makes it the right place to force a status or rewrite a title without a second save. It also hands you slashed data, and a string operation that ignores that corrupts every apostrophe.
WordPress Tutorials
A size registered with add_image_size exists for templates and nowhere else. This filter is what puts it in the Image block's Resolution dropdown, and it does nothing for images uploaded before the size was registered.
WordPress Tutorials
The filter receives a context, and the context is the whole point: widening the post context affects every call to wp_kses_post across the site, including places that trusted it to strip exactly what you just allowed.
WordPress Tutorials
The hook registers the box; it does not save anything. Saving is a second hook with a nonce, a capability check and an autosave guard, and a meta box without all three either loses data or accepts it from anyone.
WordPress Tutorials
The column needs two hooks, not one: a filter that registers the header and an action that prints each cell. A column with a header and empty cells has the first and not the second, which is the most common half-finished state.
WordPress Tutorials
The hook fires on every admin page and passes the current screen's hook suffix, which is the only thing standing between a plugin that loads one file on one screen and a plugin that slows the whole dashboard.
WordPress Tutorials
The filter receives the user on success and a WP_Error on failure, and every role-based snippet that forgets the second case throws a fatal error on a wrong password. It also only covers the standard login form, which is not the form most plugins use.
WordPress Tutorials
The filter hands you the menu as a finished HTML string, which is why it is quick for a login link and useless for anything structural. It also never fires for the Navigation block, which is most menus on block themes.
WordPress Tutorials
Both filters only touch excerpts WordPress generates. A manual excerpt is printed as written, and the Post Excerpt block sets its own length at a priority nothing in functions.php can beat.
WooCommerce
Renaming, removing and reordering entries is a one-filter job. Adding a new entry is not: the filter only prints a link, and a link to an endpoint that was never registered is a 404 the filter cannot fix.
WooCommerce
The filter hands you every calculated rate for a package, which makes hiding and repricing trivial — and the result is cached against the cart contents, so a rule that depends on anything else looks random until you know why.