seajs-compress.js

var fs = require('fs');
var gcc = require('closure-compiler')

exports.compress = function(srcFile,toFile,callback,option){
	if (!(srcFile&&toFile)){
		console.log('usage:node grunt-sea.js src-path to-path callback compress_option');
		return;
	}
	callback = callback || function(){};
	option = option || {};

	var preFunction = 'function require(){alert(arguments.length)}';
	fs.exists(srcFile, function (flag) {
		if (flag){
			fs.readFile(srcFile, "utf-8",function (err, data) {
				if (err) throw err;
				var content = data;
				//replace require and make require a global function
				content = content.replace(/define\(function\(([\w\s,]*)\)/ig, function(a,b){
					if (!b) return a;
					var arr = b.split(',');
					arr[0]='henry';
					return a.replace(b,arr.join(','));
				});
				content = preFunction + content; 

				fs.writeFile(toFile, content, {encoding:'utf8',flag:'w+'}, function (err) {
					if (err) throw err;
					gcc.compile(fs.readFileSync(toFile), {}, function(err, stdout, stderr){
						if (err) throw err;
						//delete global require function and replace define function's first argument
						var content = stdout.replace(preFunction,'');
						content =  content.replace(/define\(function\(([\w\s,]*)\)/ig, function(a,b){
							if (!b){
								return a.replace('function()','function(require)') ;	
							}else{
								var first = b.split(',')[0];
								return a.replace(b,b.replace(first,'require'))
							} 

						});

						fs.writeFile(toFile, content, {encoding:'utf8',flag:'w+'}, function (err) {
							if (err) throw err;
							callback(true,'['+toFile+'] '+srcFile+' is compressed.');
						});

					});


				});

			});		
		}else{
			callback(false,'error: src-path is not exist!');
		}
	});
}