Support Tabular Cell Merging with formatOnSave HTML Table Rendering

[cloudyparts]

Feature Request: Support Tabular Cell Merging with formatOnSave HTML Table Rendering

Proposal

Markdown tables can be rendered with merged cells using HTML comments for the original table structure. On save, the extension would convert the table to HTML, where cells with the same values are automatically merged following specific rules.

Example Markdown

Source table is hidden in and the HTML Table is rendered below the source table.

    <!---
    | 1   | 1   | 2   | 3   | 4   |
    | --- | --- | --- | --- | --- |
    | A   | B   | D   | D   | F   |
    | A   | B   | D   | D   | G   |
    | A   | C   | E   | H   | H   |
    --->

    <table border="1">
      <tr>
        <th colspan="2">1</th>
        <th>2</th>
        <th>3</th>
        <th>4</th>
      </tr>
      <tr>
        <td rowspan="3">A</td>
        <td rowspan="2">B</td>
        <td colspan="2" rowspan="2">D</td>
        <td>F</td>
      </tr>
      <tr>
        <td>G</td>
      </tr>
      <tr>
        <td>C</td>
        <td>E</td>
        <td colspan="2">H</td>
      </tr>
    </table>

Rules for Merging Cells:

1. Headers only merge columns and not rows.
2. Columns have precedence over rows when merging cells with the same content.
3. Merge first by columns, then by rows where applicable.

Benefits

• Avoids the need to manually convert tables to HTML.
• Avoids the need to write HTML for semi-complex table views.
• The tables stay easy to edit in Markdown and are rendered in HTML automatically on save, making large and complex tables easier to handle.

References

• markdown-it-merge-cells