yml-mvc-router/src/assets.js

A configurable, Express-compatible routing module that maps routes from YAML to controllers following the MVC pattern

/**
 * Handles asset injection into res.locals
 */
class Assets {
  constructor(config) {
    this.config = config;
  }

  /**
   * Create middleware to inject assets into res.locals
   * @param {Object} assets - Assets configuration from route
   * @returns {Function} Express middleware
   */
  createMiddleware(assets = {}) {
    return (req, res, next) => {
      // Initialize res.locals.assets if not exists
      if (!res.locals.assets) {
        res.locals.assets = {
          css: [],
          js: []
        };
      }

      // Add route-specific assets
      if (assets.css) {
        res.locals.assets.css.push(...this._resolveAssets(assets.css));
      }

      if (assets.js) {
        res.locals.assets.js.push(...this._resolveAssets(assets.js));
      }

      next();
    };
  }

  /**
   * Resolve asset paths
   * @param {Array|string} assetPaths - Asset path(s)
   * @returns {Array} Resolved asset URLs
   */
  _resolveAssets(assetPaths) {
    const paths = Array.isArray(assetPaths) ? assetPaths : [assetPaths];
    
    return paths.map(assetPath => {
      // If already absolute URL, return as-is
      if (assetPath.startsWith('http://') || assetPath.startsWith('https://') || assetPath.startsWith('//')) {
        return assetPath;
      }

      // If starts with /, treat as absolute path from web root
      if (assetPath.startsWith('/')) {
        return assetPath;
      }

      // Otherwise, prepend with assets base path
      return '/' + assetPath;
    });
  }

  /**
   * Generate HTML tags for assets (utility for templates)
   * @param {Array} css - CSS file paths
   * @param {Array} js - JS file paths
   * @returns {Object} { cssTag, jsTag } HTML strings
   */
  static generateTags(css = [], js = []) {
    const cssTag = css
      .map(href => `<link rel="stylesheet" href="${href}">`)
      .join('\n');

    const jsTag = js
      .map(src => `<script src="${src}"></script>`)
      .join('\n');

    return { cssTag, jsTag };
  }
}

module.exports = Assets;