save.sh

#!/usr/bin/env node

// @parameters file

/*
# Save Hook

This save hook is a Node.js script that automatically updates or adds a `date_updated` field in the YAML frontmatter of a file when it's saved. It's designed to work with text files that may or may not already have YAML frontmatter.

## Features

- Automatically adds or updates the `date_updated` field in YAML frontmatter.
- Works with files that already have frontmatter and those that don't.
- Uses the current date in ISO format (YYYY-MM-DD).
- Preserves existing frontmatter fields if present.
- Maintains consistent YAML formatting using `js-yaml`.

## Usage

To use this save hook:

1. Ensure you have Node.js installed on your system.
2. Install the required dependencies:
   ```
   npm install js-yaml
   ```

## Note

This script modifies files in-place. Always ensure you have backups of important files before running this script on them.
*/

const fs = require('fs');
const yaml = require('js-yaml');

const filePath = process.argv[2];
const content = fs.readFileSync(filePath, 'utf8');

function getCurrentDate() {
  const now = new Date();
  return now.toISOString().split('T')[0]; // Format: YYYY-MM-DD
}

function updateFrontmatter(content) {
  const frontmatterRegex = /^---\s*\n([\s\S]*?)\n---\s*\n/;
  const newDate = getCurrentDate();

  if (frontmatterRegex.test(content)) {
    // YAML frontmatter exists
    return content.replace(frontmatterRegex, (match, frontmatter) => {
      let yamlObject;
      try {
        yamlObject = yaml.load(frontmatter);
      } catch (e) {
        yamlObject = {};
      }
      yamlObject.date_updated = newDate;
      const updatedFrontmatter = yaml.dump(yamlObject, {
        lineWidth: -1,
        quotingType: '"',
        forceQuotes: false
      });
      return `---\n${updatedFrontmatter}---\n\n`;
    });
  } else {
    // No YAML frontmatter
    const newFrontmatter = yaml.dump({ date_updated: newDate }, {
      lineWidth: -1,
      quotingType: '"',
      forceQuotes: false
    });
    return `---\n${newFrontmatter}---\n\n${content}`;
  }
}

const updatedContent = updateFrontmatter(content);

fs.writeFileSync(filePath, updatedContent);