@blossom-carousel/svelte/dist/countSlideMarkers.js

A native-scroll-first carousel component for Svelte.

import { SLIDE_ATTR } from "./vendor/navigation/index.js";
/**
 * Counts elements carrying the `data-blossom-slide` attribute in an HTML
 * string (the server-rendered output of a carousel's children snippet).
 *
 * A small tag-aware scanner rather than a bare regex, so that:
 * - text content that happens to contain the literal attribute name is not
 *   counted,
 * - a `>` inside a quoted attribute value does not truncate the tag,
 * - comments are skipped.
 */
export function countSlideMarkers(html) {
    let count = 0;
    let i = 0;
    while (i < html.length) {
        if (html[i] !== "<") {
            i++;
            continue;
        }
        if (html.startsWith("<!--", i)) {
            const end = html.indexOf("-->", i + 4);
            if (end === -1)
                break;
            i = end + 3;
            continue;
        }
        // Only element open tags can carry attributes; skip closing tags,
        // doctype, and stray `<` in text.
        if (!/[a-zA-Z]/.test(html[i + 1] ?? "")) {
            i++;
            continue;
        }
        i++;
        while (i < html.length && !/[\s/>]/.test(html[i]))
            i++; // tag name
        let marked = false;
        while (i < html.length && html[i] !== ">") {
            const char = html[i];
            if (char === '"' || char === "'") {
                const closing = html.indexOf(char, i + 1);
                if (closing === -1)
                    return count; // malformed; bail out
                i = closing + 1;
                continue;
            }
            if (char === "=") {
                // Skip the value. Quoted values are handled by the branch above on
                // the next iteration; unquoted values run to whitespace or `>`.
                i++;
                while (i < html.length && /\s/.test(html[i]))
                    i++;
                if (html[i] !== '"' && html[i] !== "'") {
                    while (i < html.length && !/[\s>]/.test(html[i]))
                        i++;
                }
                continue;
            }
            if (/[\s/]/.test(char)) {
                i++;
                continue;
            }
            const start = i;
            while (i < html.length && !/[\s/=>]/.test(html[i]))
                i++;
            if (html.slice(start, i) === SLIDE_ATTR)
                marked = true;
        }
        if (marked)
            count++;
        i++;
    }
    return count;
}