wrapup-webbuilder/middleware/loadSnippets.js

A web builder for downloading browser wrapup'd JavaScript

"use strict";

var fs    = require('fs');
var async = require('async');

module.exports = function(config){

	var modules = config.modules;
	var names = Object.keys(modules);

	// where we store the result in memory, simple caching.
	var snippets;

	function loadSnippets(callback){

		async.map(names, function(name, callback){

			async.map(modules[name], function(version, callback){
				var file = config.snippetsdir + '/' + name + '-' + version + '.js';
				fs.readFile(file, 'utf-8', function(err, data){
					callback(null, err ? null : data);
				});
			}, function(err, res){
				var versions = {}, last;
				modules[name].forEach(function(version, i){
					if (res[i]){
						versions[version] = res[i];
						last = version;
					} else {
						versions[version] = {use: last};
					}
				});
				callback(null, versions);
			});

		}, function(err, results){
			var result = {};
			names.forEach(function(name, i){
				result[name] = results[i];
			});
			callback(err, result);
		});

	}

	return function(req, res, next){

		res.locals.modules = modules;

		if (snippets){
			res.locals.snippets = snippets;
			next();
			return;
		}

		loadSnippets(function(err, snip){
			if (err) return next(err);
			snippets = snip;
			res.locals.snippets = snip;
			next();
		});

	};

};