WP Interactivity API

When to use

Use this skill when the user mentions:

Interactivity API,
```
@wordpress/interactivity
```
,

data-wp-interactive

data-wp-on--*

data-wp-bind--*

data-wp-context

block
```
viewScriptModule
```
/ module-based view scripts,
hydration issues or “directives don’t fire”.

Inputs required

Repo root + triage output (
```
wp-project-triage
```
).
Which block/theme/plugin surfaces are affected (frontend, editor, both).
Any constraints: WP version, whether modules are supported in the build.

Procedure

1) Detect existing usage + integration style

Search for:

```
data-wp-interactive
```
```
@wordpress/interactivity
```
```
viewScriptModule
```

Decide:

Is this a block providing interactivity via
```
block.json
```
view script module?
Is this theme-level interactivity?
Is this plugin-side “enhance existing markup” usage?

If you’re creating a new interactive block (not just debugging), prefer the official scaffold template:

@wordpress/create-block-interactive-template

(via

@wordpress/create-block

)

2) Identify the store(s)

Locate store definitions and confirm:

state shape,
actions (mutations),
callbacks/event handlers used by
```
data-wp-on--*
```
.

3) Server-side rendering (best practice)

Pre-render HTML on the server before outputting to ensure:

Correct initial state in the HTML before JavaScript loads (no layout shift).
SEO benefits and faster perceived load time.
Seamless hydration when the client-side JavaScript takes over.

Enable server directive processing

For components using

block.json

, add

supports.interactivity

json

{
  "supports": {
    "interactivity": true
  }
}

For themes/plugins without

block.json

, use

wp_interactivity_process_directives()

to process directives.

Initialize state/context in PHP

Use

wp_interactivity_state()

to define initial global state:

php

wp_interactivity_state( 'myPlugin', array(
  'items'    => array( 'Apple', 'Banana', 'Cherry' ),
  'hasItems' => true,
));

For local context, use

wp_interactivity_data_wp_context()

php

<?php
$context = array( 'isOpen' => false );
?>
<div <?php echo wp_interactivity_data_wp_context( $context ); ?>>
  ...
</div>

Define derived state in PHP

When derived state affects initial HTML rendering, replicate the logic in PHP:

php

wp_interactivity_state( 'myPlugin', array(
  'items'    => array( 'Apple', 'Banana' ),
  'hasItems' => function() {
    $state = wp_interactivity_state();
    return count( $state['items'] ) > 0;
  }
));

This ensures directives like

data-wp-bind--hidden="!state.hasItems"

render correctly on first load.

For detailed examples and patterns, see

references/server-side-rendering.md

4) Implement or change directives safely

When touching markup directives:

keep directive usage minimal and scoped,
prefer stable data attributes that map clearly to store state,
ensure server-rendered markup + client hydration align.

WordPress 6.9 changes:

data-wp-ignore
is deprecated and will be removed in future versions. It broke context inheritance and caused issues with client-side navigation. Avoid using it.
Unique directive IDs: Multiple directives of the same type can now exist on one element using the
```
---
```
separator (e.g.,
```
data-wp-on--click---plugin-a="..."
```
and
```
data-wp-on--click---plugin-b="..."
```
).
New TypeScript types:
```
AsyncAction<ReturnType>
```
and
```
TypeYield<T>
```
help with async action typing.

For quick directive reminders, see

references/directives-quickref.md

5) Build/tooling alignment

Verify the repo supports the required module build path:

if it uses
```
@wordpress/scripts
```
, prefer its conventions.
if it uses custom bundling, confirm module output is supported.

6) Debug common failure modes

If “nothing happens” on interaction:

confirm the
```
viewScriptModule
```
is enqueued/loaded,
confirm the DOM element has
```
data-wp-interactive
```
,
confirm the store namespace matches the directive’s value,
confirm there are no JS errors before hydration.

See

references/debugging.md

Verification

wp-project-triage

indicates

signals.usesInteractivityApi: true

after your change (if applicable).

Manual smoke test: directive triggers and state updates as expected.
If tests exist: add/extend Playwright E2E around the interaction path.

Failure modes / debugging

Directives present but inert:
- view script not loading, wrong module entrypoint, or missing
```
data-wp-interactive
```
  .
Hydration mismatch / flicker:
- server markup differs from client expectations; simplify or align initial state.
- derived state not defined in PHP: use
```
wp_interactivity_state()
```
  with closures.
Initial content missing or wrong:
- ```
supports.interactivity
```
  not set in
```
block.json
```
  (for blocks).
- ```
wp_interactivity_process_directives()
```
  not called (for themes/plugins).
- state/context not initialized in PHP before render.
Layout shift on load:
- derived state like
```
state.hasItems
```
  missing on server, causing
```
hidden
```
  attribute to be absent.
Performance regressions:
- overly broad interactive roots; scope interactivity to smaller subtrees.
Client-side navigation issues (WordPress 6.9):
- ```
getServerState()
```
  and
```
getServerContext()
```
  now reset between page transitions—ensure your code doesn't assume stale values persist.
- Router regions now support
```
attachTo
```
  for rendering overlays (modals, pop-ups) dynamically.

Escalation

If repo build constraints are unclear, ask: "Is this using
```
@wordpress/scripts
```
or a custom bundler (webpack/vite)?"

Consult:

```
references/server-side-rendering.md
```
```
references/directives-quickref.md
```
```
references/debugging.md
```

wp-interactivity-api

NPX Install

Tags

SKILL.md Content