grunt-closure-compiler.js

module.exports = function(grunt) {

    'use strict';

    var exec = require('child_process').exec,
        fs = require('fs'),
        path = require('path');

    // ==========================================================================
    // TASKS
    // ==========================================================================

    grunt.registerMultiTask('closure-compiler', 'Closure Compiler.', function() {

        var closurePath = '',
            reportFile = '',
            data = this.data,
            done = this.async();

        // Check for closure path.
        if (data.closurePath) {
            closurePath = data.closurePath;
        } else if (process.env.CLOSURE_PATH) {
            closurePath = process.env.CLOSURE_PATH;
        } else {
            grunt.log.error('' +
                '/!\\'.red +
                ' Set an environment variable called ' +
                'CLOSURE_PATH'.red + ' or the build parameter' + 'closurePath'.red +
                ' and\nmake it point to your root install of Closure Compiler.' +
                '\n');
            return false;
        }

        var command = 'java -jar "' + closurePath + '/build/compiler.jar"';

        data.cwd = data.cwd || './';

        data.js = grunt.file.expand({
            cwd: data.cwd
        }, data.js);

        // Sanitize options passed.
        if (!data.js.length) {
            // This task requires a minima an input file.
            grunt.warn('Missing js property.');
            return false;
        }

        // Build command line.
        command += ' --js "' + data.js.join('" --js "') + '"';

        if (data.jsOutputFile) {
            if (!grunt.file.isPathAbsolute(data.jsOutputFile)) {
                data.jsOutputFile = path.resolve('./') + '/' + data.jsOutputFile;
            }
            command += ' --js_output_file "' + data.jsOutputFile + '"';
            reportFile = data.reportFile || data.jsOutputFile + '.report.txt';
        }

        if (data.externs) {
            data.externs = grunt.file.expand(data.externs);
            command += ' --externs ' + data.externs.join(' --externs ');

            if (!data.externs.length) {
                delete data.externs;
            }
        }

        if (data.options.externs) {
            data.options.externs = grunt.file.expand(data.options.externs);

            if (!data.options.externs.length) {
                delete data.options.externs;
            }
        }

        for (var directive in data.options) {
            if (Array.isArray(data.options[directive])) {
                command += ' --' + directive + ' "' + data.options[directive].join('" --' + directive + ' "') + '"';
            } else if (data.options[directive] === undefined || data.options[directive] === null) {
                command += ' --' + directive;
            } else {
                command += ' --' + directive + ' "' + String(data.options[directive]) + '"';
            }
        }

        data.js = grunt.file.expand({
            cwd: data.cwd
        }, data.js)

        // because closure compiler does not create dirs.
        grunt.file.write(data.jsOutputFile, '');

        // Minify WebGraph class.
        exec(command, {
            maxBuffer: data.maxBuffer * 1024,
            cwd: data.cwd
        }, function(err, stdout, stderr) {
            if (err) {
                grunt.warn(err);
                done(false);
            }

            if (stdout) {
                grunt.log.writeln(stdout);
            }

            // OK
            done();

        });

    });


};