Automattic\WooCommerce\Vendor\Pelago\Emogrifier\HtmlProcessor

AbstractHtmlProcessor::normalizeDocumentType │ private │ WC 1.0

Makes sure the document type in the passed HTML has lowercase "html".

Method of the class: AbstractHtmlProcessor{}

No Hooks.

Returns

String. HTML with normalized document type

Usage

// private - for code of main (parent) class only
$result = $this->normalizeDocumentType( $html ): string;
$html(string) (required)
.

AbstractHtmlProcessor::normalizeDocumentType() code WC 10.8.1

woocommerce/lib/packages/Pelago/Emogrifier/HtmlProcessor/AbstractHtmlProcessor.php 
private function normalizeDocumentType(string $html): string
{
    // Limit to replacing the first occurrence: as an optimization; and in case an example exists as unescaped text.
    return (new Preg())->replace(
        '/<!DOCTYPE\\s++html(?=[\\s>])/i',
        '<!DOCTYPE html',
        $html,
        1
    );
}