Add additional options into concat&uglify when use usemin

useminPrepare.js

'use strict';

module.exports = {
    html: '<%= config.web %>/index.html',
    options: {
        dest: '<%= config.dist %>',
        flow: {
            html: {
                steps: {
                    js: ['concat', 'uglifyjs']
                },
                post: {
                    js: [
                        {
                            name: 'concat',
                            createConfig: function (context, block) {
                                var generated = context.options.generated;
                                generated.options = {
                                    sourceMap: true
                                };
                            }
                        },
                        {
                            name: 'uglify',
                            createConfig: function (context, block) {
                                var generated = context.options.generated;
                                generated.options = {
                                    sourceMap: true,
                                    sourceMapIncludeSources : true,
                                    sourceMapIn : function (file) {
                                        return file + '.map';
                                    }
                                };
                            }
                        }
                    ]
                }
            }
        }
    }
};