Cli table formatter

CLI Table Formatter

Generate table formatters for structured CLI output.

Capabilities

• Create table formatters with various styles
• Configure column alignment and width
• Implement responsive table sizing
• Support Unicode borders
• Handle multiline cells
• Generate table utilities

Usage

Invoke this skill when you need to:

• Display tabular data in CLI
• Create formatted list output
• Configure column widths
• Support various border styles

Inputs

Parameter	Type	Required	Description
language	string	Yes	Target language
style	string	No	Border style (simple, unicode, markdown)
features	array	No	Required features

Generated Patterns

TypeScript Table Formatter

import chalk from 'chalk';

export interface TableColumn {
  key: string;
  header: string;
  width?: number;
  align?: 'left' | 'center' | 'right';
  format?: (value: any) => string;
}

export interface TableOptions {
  columns: TableColumn[];
  borderStyle?: 'simple' | 'unicode' | 'none' | 'markdown';
  headerColor?: (text: string) => string;
  maxWidth?: number;
}

const borders = {
  simple: {
    top: '-', bottom: '-', left: '|', right: '|',
    topLeft: '+', topRight: '+', bottomLeft: '+', bottomRight: '+',
    horizontal: '-', vertical: '|', cross: '+',
  },
  unicode: {
    top: '─', bottom: '─', left: '│', right: '│',
    topLeft: '┌', topRight: '┐', bottomLeft: '└', bottomRight: '┘',
    horizontal: '─', vertical: '│', cross: '┼',
    midLeft: '├', midRight: '┤', topMid: '┬', bottomMid: '┴',
  },
  none: {
    top: '', bottom: '', left: '', right: '',
    topLeft: '', topRight: '', bottomLeft: '', bottomRight: '',
    horizontal: '', vertical: '  ', cross: '',
  },
};

export class TableFormatter {
  private columns: TableColumn[];
  private options: TableOptions;
  private border: typeof borders.unicode;

  constructor(options: TableOptions) {
    this.options = options;
    this.columns = options.columns;
    this.border = borders[options.borderStyle || 'unicode'];
  }

  private calculateWidths(data: Record<string, any>[]): number[] {
    return this.columns.map(col => {
      const headerWidth = col.header.length;
      const maxDataWidth = Math.max(
        ...data.map(row => String(row[col.key] ?? '').length)
      );
      return col.width || Math.max(headerWidth, maxDataWidth);
    });
  }

  private padCell(text: string, width: number, align: 'left' | 'center' | 'right' = 'left'): string {
    const padding = width - text.length;
    if (align === 'center') {
      const left = Math.floor(padding / 2);
      const right = padding - left;
      return ' '.repeat(left) + text + ' '.repeat(right);
    }
    if (align === 'right') {
      return ' '.repeat(padding) + text;
    }
    return text + ' '.repeat(padding);
  }

  format(data: Record<string, any>[]): string {
    const widths = this.calculateWidths(data);
    const lines: string[] = [];
    const b = this.border;

    // Top border
    if (b.top) {
      lines.push(
        b.topLeft +
        widths.map(w => b.top.repeat(w + 2)).join(b.topMid || b.cross) +
        b.topRight
      );
    }

    // Header
    const headerCells = this.columns.map((col, i) =>
      ' ' + this.padCell(col.header, widths[i], col.align) + ' '
    );
    const headerColor = this.options.headerColor || chalk.bold;
    lines.push(
      b.left +
      headerCells.map(c => headerColor(c)).join(b.vertical) +
      b.right
    );

    // Header separator
    if (b.horizontal) {
      lines.push(
        (b.midLeft || b.left) +
        widths.map(w => b.horizontal.repeat(w + 2)).join(b.cross) +
        (b.midRight || b.right)
      );
    }

    // Data rows
    for (const row of data) {
      const cells = this.columns.map((col, i) => {
        const value = row[col.key] ?? '';
        const formatted = col.format ? col.format(value) : String(value);
        return ' ' + this.padCell(formatted, widths[i], col.align) + ' ';
      });
      lines.push(b.left + cells.join(b.vertical) + b.right);
    }

    // Bottom border
    if (b.bottom) {
      lines.push(
        b.bottomLeft +
        widths.map(w => b.bottom.repeat(w + 2)).join(b.bottomMid || b.cross) +
        b.bottomRight
      );
    }

    return lines.join('\n');
  }
}

// Quick table function
export function table(
  data: Record<string, any>[],
  columns?: (string | TableColumn)[]
): string {
  const cols: TableColumn[] = columns
    ? columns.map(c => typeof c === 'string' ? { key: c, header: c } : c)
    : Object.keys(data[0] || {}).map(key => ({ key, header: key }));

  return new TableFormatter({ columns: cols }).format(data);
}

Usage Examples

// Simple table
console.log(table([
  { name: 'Alice', age: 30, role: 'Admin' },
  { name: 'Bob', age: 25, role: 'User' },
]));

// Custom columns
const formatter = new TableFormatter({
  columns: [
    { key: 'id', header: 'ID', width: 6, align: 'right' },
    { key: 'name', header: 'Name', width: 20 },
    { key: 'status', header: 'Status', format: (v) =>
      v === 'active' ? chalk.green(v) : chalk.red(v)
    },
  ],
  borderStyle: 'unicode',
  headerColor: chalk.cyan.bold,
});

console.log(formatter.format(data));

Dependencies

{
  "dependencies": {
    "chalk": "^5.0.0"
  }
}

Target Processes

• cli-output-formatting
• dashboard-monitoring-tui
• cli-application-bootstrap