wikimedia/mediawiki-extensions-MobileFrontend

/* global $ */
/**
 * Find first paragraph that has text content, i.e. paragraphs that are not empty.
 * Keep in sync with MoveLeadParagraphTransform::identifyLeadParagraph().
 *
 * @private
 * @param {jQuery} $body Where to search for paragraphs
 * @return {Node|null} The lead paragraph
 */
module.exports = function identifyLeadParagraph( $body ) {
    // Keep in sync with MoveLeadParagraphTransform::isNotEmptyNode()
    function isNotEmptyNode( node ) {
        // Ignore VE whitespace characters
        return !/^[\s↵➞]*$/.test( node.textContent );
    }

    // Keep in sync with MoveLeadParagraphTransform::isNonLeadParagraph()
    function isNonLeadParagraph( node ) {
        node = node.cloneNode( true );
        const $node = $( node );
        // The paragraph itself can be an invisible template (T293834)
        if ( $node.hasClass( 've-ce-focusableNode-invisible' ) ) {
            return true;
        }
        // Ignore non-content nodes, TemplateStyles and coordinates
        $node.find( '.ve-ce-branchNode-inlineSlug, .ve-ce-focusableNode-invisible, style, span#coordinates' ).remove();
        if ( isNotEmptyNode( node ) ) {
            return false;
        }
        return true;
    }

    const $paragraphs = $body.children( 'p' );
    for ( let i = 0; i < $paragraphs.length; i++ ) {
        const p = $paragraphs[ i ];
        if ( !isNonLeadParagraph( p ) ) {
            return p;
        }
    }
    return null;
};