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Version: 2.2.x

Headings

Description​

Markdown headings, marked by hash characters (#), indicate different levels of content hierarchy from h1 to h6. ParsedownExtended not only supports these standard headings but also offers enhanced functionalities such as automatic permalink generation and customizable heading levels. A key feature is the ability for users to define their own logic for creating anchor IDs using the setCreateAnchorIDCallback method.

Configuration Syntax​

To configure headings in ParsedownExtended, use the config()->set() and config()->get() methods:

Getting the Current Configuration​

To retrieve the current configuration for headings:

$configValue = $ParsedownExtended->config()->get('headings');

Setting the Configuration​

To configure the headings feature:

$ParsedownExtended->config()->set('headings', (bool|array) $value);

This setting can be a boolean to globally enable or disable headings, or an array for more detailed configurations.

Configuration Options​

  • allowed_levels (array): Specify which heading levels are allowed.
  • auto_anchors (boolean): Toggle automatic permalink generation for headings.
    • blacklist (array): List of IDs to exclude from automatic anchor generation.
    • delimiter (string): Character(s) to use for separating words in anchor IDs.
    • lowercase (boolean): Whether to convert anchor IDs to lowercase.
    • transliterate (boolean): Whether to transliterate characters in anchor IDs.
    • replacements (array): List of characters to replace in anchor IDs.

Examples​

Disable Headings​

To disable headings processing:

$ParsedownExtended->config()->set('headings', false);

Custom Anchor IDs​

Use the setCreateAnchorIDCallback method to provide custom logic for generating anchor IDs:

$ParsedownExtended->setCreateAnchorIDCallback(function (string $text): string {
    return strtolower(preg_replace('/[^a-z0-9]+/i', '-', $text));
});

The callback receives the heading text as its only argument and must return the desired anchor ID string.

Configure Allowed Headings​

Specify allowed heading levels:

$ParsedownExtended->config()->set('headings.allowed_levels', ['h1', 'h2', 'h3']);

Blacklist Heading IDs​

Define a blacklist for heading IDs:

$ParsedownExtended->config()->set('headings.auto_anchors.blacklist', ['my_blacklisted_header_id', 'another_blacklisted_id']);