@blocknote/core/src/api/exporters/markdown/markdownExporter.ts

A "Notion-style" block-based extensible text editor built on top of Prosemirror and Tiptap.

import { Schema } from "prosemirror-model";

import { PartialBlock } from "../../../blocks/defaultBlocks.js";
import type { BlockNoteEditor } from "../../../editor/BlockNoteEditor.js";
import {
  BlockSchema,
  InlineContentSchema,
  StyleSchema,
} from "../../../schema/index.js";
import { createExternalHTMLExporter } from "../html/externalHTMLExporter.js";
import { EMPTY_BLOCK_PLACEHOLDER } from "../html/util/serializeBlocksExternalHTML.js";
import { htmlToMarkdown } from "./htmlToMarkdown.js";

// Needs to be sync because it's used in drag handler event (SideMenuPlugin)
export function cleanHTMLToMarkdown(cleanHTMLString: string) {
  // The external HTML exporter fills empty inline-content blocks with a
  // placeholder character so they survive an HTML round trip (see
  // `EMPTY_BLOCK_PLACEHOLDER`). Markdown has no need for that placeholder, so we
  // remove it to avoid it showing up as a stray character in the output.
  const withoutPlaceholder = cleanHTMLString
    .split(EMPTY_BLOCK_PLACEHOLDER)
    .join("");

  return htmlToMarkdown(withoutPlaceholder);
}

export function blocksToMarkdown<
  BSchema extends BlockSchema,
  I extends InlineContentSchema,
  S extends StyleSchema,
>(
  blocks: PartialBlock<BSchema, I, S>[],
  schema: Schema,
  editor: BlockNoteEditor<BSchema, I, S>,
  options: { document?: Document },
): string {
  const exporter = createExternalHTMLExporter(schema, editor);
  const externalHTML = exporter.exportBlocks(blocks, options);

  return cleanHTMLToMarkdown(externalHTML);
}