FolderTraversal.js

"use strict";

var fs = require('fs'),
	path = require('path'),
	events = require('events'),
	async = require('async');

function FolderTraversal(dir, filter) {
	function defaultFilter(v) {
		return v;
	}

	events.EventEmitter.prototype.constructor.call(this);

	var queue = [], busy = false, remaining = 0, errors = [];

	filter = filter || defaultFilter;
	var filterType = Object.prototype.toString.call(filter).slice(8, -1);
	switch (filterType) {
	case 'String':
		filter = new RegExp(filter);
	case 'RegExp':
		filter = filter.exec.bind(filter);
	case 'Function':
		break;
	default:
		throw new TypeError('filter must be a String, a RegExp or a Function');
	}

	var self = this;
	self.on('dir', function (folder, entries) {
		remaining += entries.length;

		entries.forEach(function (entry) {
			var fullEntry = path.join(folder, entry);
			fs.stat(path.join(dir, fullEntry), function (err, stat) {
				if (err) {
					errors.push(err);
				} else {
					var m;
					if (stat && stat.isDirectory()) {
						self.emit('run', fullEntry);
					} else if ((m = filter(entry))) {
						self.emit('file', fullEntry, m);
					}
				}
				if (--remaining === 0) {
					self.emit('end', errors.length ? errors : null);
				}
			})
		});
	});
	self.on('processQueue', function() {
		queue.forEach(function (folder) {
			fs.readdir(path.join(dir, folder), function (err, entries) {
				if (err) {
					errors.push(err);
				} else {
					self.emit('dir', folder, entries);
				}
				if (--remaining === 0) {
					self.emit('end', errors.length ? errors : null);
				}
			});
		});
		queue = [];
		busy = false;
	});
	self.on('run', function (folder) {
		++remaining;
		queue.push(folder || null);
		if (!busy) {
			process.nextTick(function () {
				self.emit('processQueue');
			});
			busy = true;
		}
	});
}
FolderTraversal.prototype = Object.create(events.EventEmitter.prototype);
FolderTraversal.prototype.constructor = FolderTraversal;
FolderTraversal.traverse = function(dir, filter, iterator, callback) {
	var traverse = new FolderTraversal(dir, filter);
	traverse.on('file', iterator);
	traverse.on('end', function(err) {
		callback(err);
	});
	traverse.emit('run');
};



/* Example: 

FolderTraversal.traverse(
	'assets',
	/^([^@]+)(?:@([^\.]+))?\.(.+)$/,
	function(fn, match) {
		console.log([fn, match]);
	},
	function(errors) {
		console.log('EOT. Errors: ' + errors);
	}
);
*/