@tanstack/markdown/dist/extensions/autolinks.js

A tiny, fast, deterministic Markdown renderer for blogs and documentation.

const protocol = /https?:\/\//iy;
const boundary = /(?<=[\p{L}\p{N}\p{M}_/@<\\])/uy;
const terminator = /[\s\u0000-\u0020\u007f<>"'`\\]/;
const trailing = /[.,!?;:]/;
/** Opt-in HTTP(S) links; leaves the core Markdown profile unchanged. */
export function autolinksExtension() {
    return { name: 'autolinks', inlineParser: { markers: 'hH<', parse: parseAutolink } };
}
function parseAutolink({ source, index, options, inLink }) {
    if (inLink)
        return;
    const angle = source[index] === '<';
    boundary.lastIndex = index;
    if (!angle && boundary.test(source))
        return;
    const start = index + Number(angle);
    protocol.lastIndex = start;
    if (!protocol.test(source))
        return;
    let end = protocol.lastIndex;
    const depth = [0, 0, 0];
    while (end < source.length) {
        const char = source[end];
        if (terminator.test(char))
            break;
        if (!angle) {
            const open = '([{'.indexOf(char);
            const close = ')]}'.indexOf(char);
            if (open !== -1)
                depth[open]++;
            if (close !== -1 && depth[close]-- === 0)
                break;
        }
        end++;
    }
    if (!angle)
        while (end > protocol.lastIndex && trailing.test(source[end - 1]))
            end--;
    const url = source.slice(start, end);
    const closed = !angle || source[end] === '>';
    const length = end + Number(angle && closed) - index;
    let valid = closed;
    if (valid)
        try {
            new URL(url);
        }
        catch {
            valid = false;
        }
    // Consume malformed candidates literally so their suffixes are not rescanned.
    // Only validated URLs reach the application's trusted replacement policy.
    const href = valid ? options.urlTransform ? options.urlTransform(url, 'link', url) : url : null;
    const label = { type: 'text', value: valid ? url : source.slice(index, index + length) };
    return { length, node: href ? { type: 'link', href, children: [label] } : label };
}