Code Formatter

A skill to automatically format code files using language-specific formatters.

Overview

This skill helps format code files by detecting the programming language and applying the appropriate formatter. It supports JavaScript/TypeScript (Prettier), Python (Black), and Rust (rustfmt), providing clear feedback on formatting changes.

When to Use

Use this skill when you need to format code files to match standard style guides, prepare code for commits, or ensure consistent formatting across a project.

Instructions

Step 1: Validate Input File

Check that the specified file exists and is readable.

if [ ! -f "$FILE_PATH" ]; then
    echo "Error: File not found"
    exit 1
fi

Step 2: Detect File Language

Determine the programming language based on file extension.

case "$FILE_PATH" in
    *.js|*.jsx|*.ts|*.tsx)
        FORMATTER="prettier"
        ;;
    *.py)
        FORMATTER="black"
        ;;
    *.rs)
        FORMATTER="rustfmt"
        ;;
    *)
        echo "Error: Unsupported file type"
        exit 1
        ;;
esac

Step 3: Check Formatter Installation

Verify the required formatter is installed.

if ! command -v $FORMATTER &> /dev/null; then
    echo "Error: $FORMATTER not installed"
    exit 1
fi

Step 4: Run Formatter

Execute the formatter on the file.

case "$FORMATTER" in
    prettier)
        prettier --write "$FILE_PATH"
        ;;
    black)
        black "$FILE_PATH"
        ;;
    rustfmt)
        rustfmt "$FILE_PATH"
        ;;
esac

Step 5: Report Results

Display what was changed.

echo "Formatted $FILE_PATH with $FORMATTER"

Examples

Example 1: Format a JavaScript file

• Input: format src/app.js
• Output: Formatted src/app.js with prettier

Example 2: Format a Python file

• Input: format main.py
• Output: Formatted main.py with black