templating.js

var fs = require("fs");
require('josi/class');

var TemplatingEngine = Class.extend({
  init: function() {
    var cache = {};
    var self = this;
    this.load = function(path, cb) {
      if (cache[path]) {
        cb(cache[path]);
      } else {
        fs.readFile(path, 'utf8', function(err, data) {
          if (err) {
            // todo: deal with error when loading view
            throw err;
          }
          cache[path] = self.compile(data);
          cb(cache[path]);
        });
      }
    };
  },
  compile: function(str) {
    throw new Error('Not implemented error. To use create a subclass of TemplatingEngine that implements compile.');
  },
  render: function(data, callback, view, master) {
    var self = this;
    this.load(view, function(template) {
      var rendered = template(data);
      if (master) {
        // fixme: don't clobber users' data
        data.main = rendered;
          self.load(master, function(masterTemplate) {
          var rendered = masterTemplate(data);
          callback(rendered);
        });
      } else {
        callback(rendered);
      }
    });
  }
});

// JavaScript Micro-Templating
// by John Resig - http://ejohn.org/ - MIT Licensed
// http://ejohn.org/blog/javascript-micro-templating/
this.MicroTemplatingEngine = TemplatingEngine.extend({
  compile: function(str) {
    return new Function("obj",
      "var __=[];" +

      // Introduce the data as local variables using with(){}
      "with(obj){__.push('" +

      // Convert the template into pure JavaScript
      str
        .replace(/[\r\n\t]/g, " ")
        .split("<%").join("\t")
        .replace(/((^|%>)[^\t]*)'/g, "$1\r")
        .replace(/\t=(.*?)%>/g, "',$1,'")
        .split("\t").join("');")
        .split("%>").join("__.push('")
        .split("\r").join("\\'")
      + "');}return __.join('');"
    );
  }
});

// Adapted from jQuery Templating Plugin
// Copyright 2010, John Resig
// Dual licensed under the MIT or GPL Version 2 licenses.
// http://github.com/jquery/jquery-tmpl/
this.jQueryTemplatingEngine = TemplatingEngine.extend({
  compile: function(str) {
    var tmplcmd = {
      'each': {
        _default: [null, "$i"],
        prefix: "for(var $2 in $1){",
        suffix: "}"
      },
      'if': {
        prefix: "if($1){",
        suffix: "}"
      },
      'else': {
        prefix: "}else{"
      },
      '=': {
        _default: ["this"],
        prefix: "_.push(typeof $1==='function'?$1.call(this):$1);"
      }
    };
    var fn = new Function("$data",
      "var _=[];_.data=$data;" +

      // Introduce the data as local variables using with(){}
      "with($data){_.push('" +

      // Convert the template into pure JavaScript
      str
        .replace(/[\r\t\n]/g, " ")
        .replace(/\${([^}]*)}/g, "{{= $1}}")
        .replace(/{{(\/?)(\w+|.)(?:\((.*?)\))?(?: (.*?))?}}/g, function(all, slash, type, fnargs, args) {
          var tmpl = tmplcmd[type];

          if (!tmpl) {
            throw "Template command not found: " + type;
          }

          var def = tmpl._default;

          return "');" + tmpl[slash ? "suffix" : "prefix"]
            .split("$1").join(args || (def ? def[0] : ''))
            .split("$2").join(fnargs || (def ? def[1] : '')) + "_.push('";
        })
      + "');}return _.join('');");
    return fn;
  }
});