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Validation API Core Blocks

Registers Validation API checks for WordPress core blocks.

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

★ 0stars

Install

Download source zip No release zip yet

This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.

Install straight from GitHub with WP-CLI:

wp plugin install https://github.com/troychaplin/validation-api-core-blocks/archive/refs/heads/main.zip
No built-in updater. New versions won't appear under Dashboard → Updates. Install new releases yourself, or let Git Updater track the repository.
Readme github.com/troychaplin/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