#1 checking modified dates of file before minifying

lib/util.js

@@ -1,4 +1,5 @@
 var _ = require("underscore"),
+	fs = require('fs'),
 	path = require('path');
 
 module.exports = {
@@ -64,6 +65,19 @@ module.exports = {
 			}
 		}
 		return destination;
+	},
+
+	// compares a file against a list of dependencies to check if there are updates
+	hasUpdates: function(master, deps){
+		var update = false;
+		var last = fs.statSync(master).mtime.getTime();
+		// assume deps are in an array
+		for( var i in deps ){
+			var file = deps[i];
+			var modified = fs.statSync(file).mtime.getTime();
+			if( modified > last ) update = true;
+		}
+		return update;
 	}
 
 }

tasks/js.js

@@ -1,4 +1,5 @@
 var fs = require("fs"),
+	u = require("../lib/util"),
 	_ = require("underscore");
 
 module.exports = function (grunt) {
@@ -40,6 +41,9 @@ module.exports = function (grunt) {
 					continue;
 				}
 			}
+			// - proceed only if there's a newer file
+			var updates  = u.hasUpdates(lib, scripts);
+			if( !updates ) continue;
 
 			// in all other cases add the task
 			config.uglify[group] = {

tasks/lessc.js

@@ -1,4 +1,5 @@
 var fs = require("fs"),
+	u = require("../lib/util"),
 	_ = require("underscore");
 
 module.exports = function (grunt) {
@@ -46,11 +47,15 @@ module.exports = function (grunt) {
 				var now = (new Date()).getTime();
 				var modified = fs.statSync(lib).mtime.getTime();
 				// stop now if it's too early
-				console.log("less: now - modified", (now - modified) );
 				if( now - modified < this.data.timeout ){
 					continue;
 				}
 			}
+			// - proceed only if there's a newer file
+			var files = getLessFiles( styles );
+			var updates  = u.hasUpdates(lib, files);
+			if( !updates ) continue;
+
 			// in all other cases add the task
 			config.less.compile.files[lib] = styles;
 
@@ -70,3 +75,20 @@ module.exports = function (grunt) {
 
 
 };
+
+
+// Helpers
+
+getLessFiles = function( files ){
+	var result = [];
+	for( var i in files ){
+		var file = files[i];
+		var path = file.substring(0,file.lastIndexOf("/")+1);
+		var contents = fs.readdirSync( path ); // get all files in the dir..
+		// add the path to the contents
+		for( var j in contents ){
+			result.push( path + contents[j] );
+		}
+	}
+	return result;
+}