JS GCC compile or remove GCC globals

build.js

#!/usr/bin/env node

if (process.argv.length < 3) {
	console.error('No enough parameters');
	process.exit();
}

const fs = require('fs')
	, path = require('path')
;

var argv = process.argv
	, file = argv[2]
	, mode = (argv[3] || "GCC_A").toUpperCase()
	, gccMode
	, output = argv[4] || file

	, i
	, k
	, str
;

file = fs.readFileSync(file) + "";

switch(mode) {
	case "RG":
		file = file.replace(/\/\/\s*\[\[\[\|\|\|---=== GCC DEFINES START ===---\|\|\|\]\]\]([\s\S]*)\/\/\s*\[\[\[\|\|\|---=== GCC DEFINES END ===---\|\|\|\]\]\]/i, function(a, find) {
			str = find;
			return "";
		});
		if(str) {
			file = file.replace(/"use strict"\s*;\s*\n/, '"use strict";\n' + str + "\n");

			fs.writeFileSync(output, file);
		}
	break;
	case "GCC_W":
		if(!gccMode)gccMode = "WHITESPACE_ONLY";
	case "GCC_S":
		if(!gccMode)gccMode = "SIMPLE_OPTIMIZATIONS";
	case "GCC_A":
		if(!gccMode)gccMode = "ADVANCED_OPTIMIZATIONS";

		i = require('http').request({
			host:		'closure-compiler.appspot.com'
			, port:		80
			, method:	'POST'
			, headers:	{ "Content-Type": "application/x-www-form-urlencoded" }
			, path:		'/compile'
		}, function (res){
			var body = '';
			res.on('data', function (data){ body += data; });
			res.on('end', function () {
				fs.writeFileSync(output, body);
			});
		});

		i.write(require('querystring').stringify({
				js_code: file
				//DEFAULT
				, compilation_level: gccMode
				//, formatting : 'pretty_print'
				, output_format: 'text'
				//	, output_info: 'errors'
				, output_info: 'compiled_code'
			})
		);

		i.end();

	break;
}

example.md

node build.js input.js -> GCC Advanced mode, output is 'input.js'
node build.js input.js GCC_A output.js -> GCC Advanced mode, output is 'output.js'
node build.js input.js GCC_S -> GCC Simple mode, output is 'input.js'
node build.js input.js GCC_W -> GCC Whitespace only mode, output is 'input.js'
node build.js input.js RG -> Remove global mode, output is 'input.js'