LoDash Template Loader

lodash-loader.js

/* Lo-Dash Template Loader v0.1.0
 * Copyright 2013, Tim Branyen (@tbranyen).
 * lodash-loader.js may be freely distributed under the MIT license.
 *
 * Configure in your RequireJS configuration:
 *
 * // You can name the plugin prefix whatever you like.
 * paths: {
 *   "lo": "path/to/amd_template"
 * },
 * 
 * // Options below are the defaults.
 * _templateSettings: {
 *   ext: ".html",
 *   root: "/"
 * }
 *
 * And then you can use simply:
 *
 * // Omit the extension and root path.
 * require(["lo!path/to/template"], function(template) {
 *   var contents = template({
 *     // Some data.
 *   });
 * });
 *
 * This template loader plugin works in both RequireJS and R.js bundled with Almond.
 *
 * Should support Dojo as well. (Untested).
 *
 */
(function(global) {
"use strict";

// Cache used to map configuration options between load and write.
var buildMap = {};

// Alias the correct `nodeRequire` method.
var nodeRequire = requirejs.nodeRequire;

// If in Node, get access to the filesystem.
if (nodeRequire) {
  fs = nodeRequire("fs");
}

// Define the plugin using the CommonJS syntax.
define(function(require, exports) {
  var _ = require("lodash");

  exports.version = "0.1.0";

  // Invoked by the AMD builder, passed the path to resolve, the require
  // function, done callback, and the configuration options.
  exports.load = function(name, req, load, config) {
    // Dojo provides access to the config object through the req function.
    if (!config) {
      config = require.rawConfig;
    }

    // Always keep a copy of the original name.
    var originalName = name;

    // Default settings point to the project root and using html files.
    var settings = _.defaults(config._templateSettings, {
      ext: ".html",
      root: "/"
    });

    // Builds must happen with Node.
    if (config.isBuild) {
      name = settings.root + name + settings.ext;

      // Remove a leading forward slash during builds.
      if (name[0] === "/") {
        name = name.slice(1);
      }

      // Read in the file synchronously, as RequireJS expects, and return the
      // contents.  Process as a Lo-Dash template.
      buildMap[originalName] = _.template(String(fs.readFileSync(name)));

      return load();
    }

    // Create a basic XHR.
    var xhr = new XMLHttpRequest();

    // Wait for it to load.
    xhr.onreadystatechange = function() {
      if (xhr.readyState === 4) {
        // Process as a Lo-Dash template and cache.
        buildMap[name] = _.template(xhr.responseText);

        // Return the compiled template.
        load(buildMap[name]);
      }
    };

    // Ensure the root always end in a trailing slash.
    if (settings.root[settings.root.length-1] !== "/") {
      settings.root = settings.root + "/";
    }

    // Initiate the fetch.
    xhr.open("GET", settings.root + name + settings.ext, true);
    xhr.send(null);
  };

  // Also invoked by the AMD builder, this writes out a compatible define
  // call that will work with loaders such as almond.js that cannot read
  // the configuration data.
  exports.write = function(pluginName, moduleName, write) {
    var template = String(buildMap[moduleName]);

    // This will return the template.
    var retTemplate = [
      "function() {",
        "return ", template, ";",
      "}"
    ].join("");

    // Write out the actual definition
    write([
      "define('", pluginName, "!", moduleName, "', ", "[], ",
        retTemplate,
      ");\n"
    ].join(""));
  };
});

})(typeof global === "object" ? global : this);