manifest / editor / validation-api-core-blocks

Validation API Core Blocks

Registers Validation API checks for WordPress core blocks.

by Troy Chaplin · github.com/troychaplin/validation-api-core-blocks

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Install

No release zip yet. The repository archive installs, but the folder name will carry the branch suffix and updates will not flow:

wp plugin install https://github.com/troychaplin/validation-api-core-blocks/archive/refs/heads/main.zip

Readme

Validation API Core Blocks

Registers Validation API checks for WordPress core blocks. All checks are block-level — no custom post types, no meta fields, no custom blocks.

Requires: The Validation API plugin must be active. If it is not, this plugin loads silently without registering any checks.

Checks

`core/image`

Check	Default	Description
`check_image_alt_text`	error	Alt text is required once an image is selected. Decorative images (`isDecorative`) are exempt.
`check_image_alt_text_length`	error	Alt text must not exceed 125 characters.
`check_image_alt_caption_match`	error	Alt text and caption must not be identical.
`check_image_alt_text_patterns`	error	Alt text must not be a filename, a single generic word (`image`, `photo`, `pic`, …), or a short phrase starting with `image of`, `photo of`, etc.

`core/button`

Check	Default	Description
`check_button_link`	error	A valid URL is required. `<button>` elements (no navigation intent) are exempt.
`check_button_text`	error	Button text must be present and contain at least one alphanumeric character.

`core/table`

Check	Default	Description
`check_table_headers`	error	The table must have a header section (`<thead>`) or header cells (`<th>`) in the first row.

`core/heading`

Check	Default	Description
`check_heading_rank`	error	Heading levels must not skip ranks (e.g. H2 → H4). The first heading in the document must be H1 or H2.

Severity for any check can be overridden at runtime without touching this plugin's code via the validation_api_check_level filter provided by the Validation API.

File Structure

validation-api-core-blocks/
├── Functions/
│   ├── Check_Core_Button.php     # Registers core/button checks
│   ├── Check_Core_Heading.php    # Registers core/heading checks
│   ├── Check_Core_Image.php      # Registers core/image checks
│   ├── Check_Core_Table.php      # Registers core/table checks
│   ├── Enqueues.php              # Enqueues editor-script.js
│   └── Plugin_Paths.php          # Plugin URL / path helpers
├── src/
│   ├── editor-script.js          # Entry point — imports all check files
│   └── scripts/
│       ├── checks/
│       │   ├── core-button.js    # editor.validateBlock logic for core/button
│       │   ├── core-heading.js   # editor.validateBlock logic for core/heading
│       │   ├── core-image.js     # editor.validateBlock logic for core/image
│       │   ├── core-table.js     # editor.validateBlock logic for core/table
│       │   └── editor-checks.js  # editor.validateEditor scaffold (empty)
│       └── utils/
│           └── isValidUrl.js     # Lightweight URL validator
├── plugin.php
└── README.md

Adding a New Check

1. Register the check in PHP

Create Functions/Check_Core_Paragraph.php (or add to an existing class):

namespace Validation_API_Core_Blocks;

class Check_Core_Paragraph {
    public function __construct() {
        add_action( 'init', array( $this, 'register_checks' ) );
    }

    public function register_checks() {
        if ( ! function_exists( 'validation_api_register_block_check' ) ) {
            return;
        }

        validation_api_register_block_check(
            'core/paragraph',
            array(
                'namespace'   => 'validation-api-core-blocks',
                'name'        => 'check_paragraph_not_empty',
                'level'       => 'error',
                'error_msg'   => __( 'Paragraph blocks must not be empty.', 'validation-api-core-blocks' ),
                'warning_msg' => __( 'Consider removing empty paragraphs.', 'validation-api-core-blocks' ),
                'description' => __( 'Paragraph blocks require content.', 'validation-api-core-blocks' ),
            )
        );
    }
}

Instantiate it in plugin.php:

\Validation_API_Core_Blocks\Check_Core_Paragraph::class,

2. Implement the validation logic in JavaScript

Create src/scripts/checks/core-paragraph.js:

import { addFilter } from '@wordpress/hooks';

addFilter(
    'editor.validateBlock',
    'validation-api-core-blocks/paragraphValidation',
    (isValid, blockType, attributes, checkName) => {
        if (blockType !== 'core/paragraph') {
            return isValid;
        }

        switch (checkName) {
            case 'check_paragraph_not_empty':
                return !!(attributes.content && attributes.content.trim());
            default:
                return isValid;
        }
    }
);

Import it in src/editor-script.js:

import './scripts/checks/core-paragraph.js';

Development

# Install dependencies
npm install
composer install

# Development build with watch mode
npm run start

# Production build
npm run build

# Lint and format
npm run lint
npm run format

Read the full README on GitHub →