templateFinder.js

var cachedTemplates = {};

module.exports = function(Handlebars) {

  /**
   * Provide a way for apps to specify that different template name patterns
   * should use different compiled template files.
   *
   */
  var templatePatterns = [];

  /**
   * Given a template name, return the compiled Handlebars template.
   */
  function getTemplate(templateName) {
    /**
     * Find the correct source file for this template.
     */
    var src = getSrcForTemplate(templateName);

    /**
    * Allow compiledTemplates to be created asynchronously by lazy-requiring it.
    */
    if (!cachedTemplates[src]) {
      cachedTemplates[src] = require(src);

      /**
       * Make it play nicely with both AMD and CommonJS.
       * The `grunt-contrib-handlebars` module  produces different stucture
       * of compiled templates with `amd` vs `commonjs` options. Accommodate
       * both options here. the `amd` option results in templates as an Object,
       * whereas the `commonjs` option results in templates as a Function.
       */
      if (typeof cachedTemplates[src] == 'function') {
        cachedTemplates[src] = cachedTemplates[src](Handlebars);
      }
    }

    return cachedTemplates[src][templateName];
  }

  /**
   * For a given template name, find the correct compiled templates source file
   * based on pattern matching on the template name.
   */
  function getSrcForTemplate(templateName) {
    var currentPattern = templatePatterns.filter(function(obj) {
      return obj.pattern.test(templateName);
    })[0];

    if (currentPattern == null) {
      throw new Error('No pattern found to match template "' + templateName + '".');
    }

    return currentPattern.src;
  }

  return {
    getTemplate: getTemplate,
    getSrcForTemplate: getSrcForTemplate,
    templatePatterns: templatePatterns
  }
};