@atlaskit/editor-core/src/transformers/bitbucket/tableSerializer.ts

A package contains Atlassian editor core functionality

import {
  MarkdownSerializerState,
  Node as PMNode,
} from '../../prosemirror';

const isHeaderRow = (row: PMNode): boolean => row.child(0).type.name === 'tableHeader';

const isHeaderRowPresent = (table: PMNode): boolean => {
  let headerRowPresent = false;
  table.content.forEach((row: PMNode, i: number) => {
    if (isHeaderRow(row)) {
      headerRowPresent = true;
    }
  });
  return headerRowPresent;
};

const renderNode = (state: MarkdownSerializerState, node: PMNode, index: number): void => {
  if (index > 0) {
    state.write(' ');
  }
  node.content.forEach((child: PMNode, i: number) => {
    if (child.isTextblock) {
      if (i > 0) {
        state.write(' ');
      }
      state.renderInline(child);
    }
    else {
      renderNode(state, child, i);
    }
  });
};

const renderInlineContent = (state: MarkdownSerializerState, node: PMNode) => {
  state.write('| ');
  renderNode(state, node, 0);
  state.write(' ');
};

export default {
  table(state: MarkdownSerializerState, node: PMNode) {
    if (isHeaderRowPresent(node)) {
      node.content.forEach((child, i) => state.render(child, node, i));
      state.closeBlock(node);
    }
  },
  tableRow(state: MarkdownSerializerState, node: PMNode) {
    node.content.forEach((child, i) => {
      state.render(child, node, i);
    });
    state.write('|');
    state.ensureNewLine();
    if (isHeaderRow(node)) {
      for(let i = 0; i < node.childCount; i++) {
        state.write('| --- ');
      }
      state.write('|');
      state.ensureNewLine();
    }
  },
  tableHeader: renderInlineContent,
  tableCell: renderInlineContent,
};