@tanstack/markdown/dist/html/streaming.js

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

import { parseMarkdown } from '../parser.js';
import { renderHtml } from '../html.js';
import { streamingMarkdownExtension } from '../extensions/streaming.js';
import { escapeHtml } from '../utils.js';
function optionsFor(base, options) {
    return options === undefined ? base : { ...options, extensions: [...base.extensions, ...(options.extensions ?? [])] };
}
export function createStreamingHtmlRenderer() {
    const base = { extensions: [streamingMarkdownExtension()] };
    let state;
    let profileExposed = false;
    function full(source, options) {
        state = undefined;
        return renderHtml(source, optionsFor(base, options));
    }
    function fenced(source) {
        const header = source.match(/^(`{3,}|~{3,})[^\n]*\n/);
        if (!header || source.includes('\r') || source.charCodeAt(0) === 0xFEFF)
            return full(source);
        const body = source.slice(header[0].length);
        if (/^ {0,3}[`~]/m.test(body))
            return full(source);
        if (!body)
            return full(source);
        let ownedSource, output, suffix;
        if (state && source.startsWith(state.source)) {
            const delta = source.slice(state.source.length);
            if (!delta) {
                return state.html;
            }
            suffix = state.suffix;
            ownedSource = [state.source, delta].join('');
            output = [state.html.slice(0, -suffix.length), escapeHtml(delta), suffix].join('');
        }
        else {
            const document = parseMarkdown(header[0], base);
            if (document.children.length !== 1 || document.children[0]?.type !== 'code')
                return full(source);
            const empty = renderHtml(document, base);
            const end = empty.indexOf('</code>');
            if (end === -1)
                return full(source);
            const prefix = empty.slice(0, end);
            suffix = empty.slice(end);
            ownedSource = [header[0], body].join('');
            output = [prefix, escapeHtml(body), suffix].join('');
        }
        state = { source: ownedSource, html: output, suffix };
        return output;
    }
    return { reset() { state = undefined; }, render(source, options) {
            // Options hooks can retain and mutate the internal extension after this call.
            if (options !== undefined)
                profileExposed = true;
            if (profileExposed || typeof source !== 'string' || (source[0] !== '`' && source[0] !== '~'))
                return full(source, options);
            return fenced(source);
        } };
}