silverbullet/plugs/markdown/api.ts

import {
  findNodeOfType,
  ParseTree,
  renderToText,
  replaceNodesMatchingAsync,
} from "$sb/lib/tree.ts";
import { codeWidget } from "$sb/syscalls.ts";
import { parseMarkdown } from "$sb/silverbullet-syscall/markdown.ts";
import {
  MarkdownRenderOptions,
  renderMarkdownToHtml,
} from "./markdown_render.ts";

/**
 * Finds code widgets, runs their plug code to render and inlines their content in the parse tree
 * @param mdTree parsed markdown tree
 * @param pageName name of the current page
 * @returns modified mdTree
 */
export async function expandCodeWidgets(
  mdTree: ParseTree,
  pageName: string,
): Promise<ParseTree> {
  await replaceNodesMatchingAsync(mdTree, async (n) => {
    if (n.type === "FencedCode") {
      const codeInfo = findNodeOfType(n, "CodeInfo");
      if (!codeInfo) {
        return;
      }
      const codeType = codeInfo.children![0].text!;
      const codeTextNode = findNodeOfType(n, "CodeText");
      try {
        // This will error out if this is not a code wiget, which is fine
        const result = await codeWidget.render(
          codeType,
          renderToText(codeTextNode!),
          pageName,
        );
        if (!result) {
          return {
            text: "",
          };
        }
        // Only do this for "markdown" widgets, that is: that can render to markdown
        if (result.markdown !== undefined) {
          const parsedBody = await parseMarkdown(result.markdown);
          // Recursively process
          return expandCodeWidgets(
            parsedBody,
            pageName,
          );
        }
      } catch (e: any) {
        // 'not found' is to be expected (no code widget configured for this language)
        // Every other error should probably be reported
        if (!e.message.includes("not found")) {
          console.error("Error rendering code", e.message);
        }
      }
    }
  });
  return mdTree;
}

export async function markdownToHtml(
  markdown: string,
  options: MarkdownRenderOptions = {},
) {
  const mdTree = await parseMarkdown(markdown);
  return renderMarkdownToHtml(mdTree, options);
}