markdown-tables

name	markdown-tables
description	Formats markdown tables with fixed-width columns for consistent alignment. Use when creating tables, reformatting existing tables, or ensuring table readability. Triggers on terms like "format table", "align table", "fix table", "table columns", "markdown table".

Markdown Table Formatting Skill

Markdown tables MUST use fixed-width columns with space padding. This is mandatory for readability in plain text editors and diffs.

Correct vs Incorrect Format

Correct: Fixed-width columns with padding

| Size     | succinctly          | jq                  | Speedup    |
|----------|---------------------|---------------------|------------|
| **10KB** | 2.2 ms (4.3 MiB/s)  | 4.1 ms (2.3 MiB/s)  | **1.86x**  |
| **1MB**  | 24.5 ms (33 MiB/s)  | 44 ms (18 MiB/s)    | **1.79x**  |

Incorrect: Unpadded columns

| Size | succinctly | jq | Speedup |
|------|------------|-----|---------|
| **10KB** | 2.2 ms (4.3 MiB/s) | 4.1 ms (2.3 MiB/s) | **1.86x** |

Column Width Rules

1. Measure the widest content in each column (including header)
2. Pad all cells to match the widest cell in that column
3. Use spaces for alignment, not tabs
4. Align text left, numbers can be right-aligned for decimals
5. Leave one space after | and before | for readability in data rows
6. Separator row has NO spaces - format as |------|---------| with dashes matching column widths
7. Empty cells use single dash "-" padded with spaces: | - |

Formatting Algorithm

For each column:
  1. width = max(len(cell) for cell in column)
  2. width = max(width, 3)  # Minimum 3 chars for separator

For each row:
  1. For each cell:
     - Pad content to column width
     - Add single space before and after content
  2. Join cells with '|' delimiter
  3. Add '|' at start and end

Bold Text in Tables

When using bold (**text**) in table cells:

Spaces must be OUTSIDE the bold markers, not inside:

<!-- CORRECT: Spaces outside ** -->
|   **59.6ms** |

<!-- WRONG: Spaces inside ** (markdown won't render bold) -->
| ** 59.6ms** |

This is important for right-aligned numeric columns where padding is added.

Alignment Markers

Alignment	Separator Format	Example
Left	`	----------
Right	`	---------:
Center	`	:--------:

Complex Tables

For tables with many columns or very long content:

| Name       | Type   | Size    | Description                          |
|------------|--------|---------|--------------------------------------|
| ib         | Vec    | ~N bits | Interest bits marking structural     |
|            |        |         | characters and value starts          |
| bp         | Vec    | ~N bits | Balanced parens encoding tree        |
|            |        |         | structure                            |

Consider:

• Splitting into multiple smaller tables
• Using a different format (bullet lists, nested structure)
• Rotating the table (rows become columns)

Why Fixed-Width Tables Matter

1. Readability in Git Diffs: Variable-width tables are hard to review in diff views
2. Text Editor Alignment: Most code reviews happen in monospace fonts
3. Terminal Display: Tables render correctly in terminal viewers
4. Professional Appearance: Shows attention to detail
5. Easier Maintenance: Clear structure makes updates simpler

Instructions

When formatting tables:

1. Read the table - Identify all rows and columns
2. Calculate widths - Find max content width per column
3. Format header - Apply consistent width with padding
4. Format separator - Match column widths with dashes
5. Format data rows - Apply same widths to all cells
6. Preserve alignment - Keep : markers for right/center alignment