angular.middleware.js

var path = require('path');
var fs = require('fs');
var cheerio = require('cheerio');

var createTemplate = function(id, markup) {
  var $ = cheerio.load('<script type="text/ng-template"></script>');
  $('script').attr('id', id).html(markup).html();
  return $.html();
};

var preload = function(filePath, options) {
  if (!fs.existsSync(filePath)) throw new Error(filePath + ' doesn\'t exist');

  var content = fs.readFileSync(filePath);
  var $ = cheerio.load(content);
  options = Object(options);

  $('[ng-include]').each(function(i, el) {
    var templateUrl = el.attribs['ng-include'].replace(/^'|'$/g, '');
    var templatePath = path.resolve('client', templateUrl);
    if (fs.existsSync(templatePath)) {
      if (options.cacheTemplates) {
        // Appends <script> tags to populate $templateCache (https://docs.angularjs.org/api/ng/service/$templateCache)
        $('head').append(createTemplate(templateUrl, fs.readFileSync(templatePath)));
      } else {
        // Injects the template's content into the element
        $(el).removeAttr('ng-include').html(fs.readFileSync(templatePath));
      }
    }
  });

  var markup = $.html();
  return function(req, res, next) {
    res.send(markup);
  };
};

module.exports = {
  preload: preload
};