インデントや複数行続く改行を削除（script, style 要素は除外）

Gruntfile.js

module.exports = function(grunt)
{
    'use strict';

    grunt.config.init({
        html_clean: {
            html: {
                src: 'sample.html',
                newline: '\r\n', // 省略可
            },
        },
    });

    grunt.task.registerMultiTask('html_clean',
        'delete empty lines and indent',
        function() {
            var self   = this,
                config = grunt.config.get(this.name),
                files  = grunt.file.expand(this.data.src);

            files.forEach(function(file) {
                var dest, matches, nl, mSrc, mDest,
                    conf = config[self.target] || {},
                    nl   = conf.newline,
                    src  = grunt.file.read(file),
                    pattern = /<(script|style)\b[\s\S]*?>([\s\S]*?)<\/\1\b[\s\S]*?>/igm;

                matches = src.match(/\r\n|\n|\r/);
                if (!nl) {
                    nl = matches ? matches[0] : '\n';
                }

                mSrc = src.match(pattern);
                dest = src.replace(/\r\n|\n|\r/gm, '\n');
                dest = dest.replace(/^([\s\t\r\n\0\0xB]*|\n*$)/gm, '');
                dest = dest.replace(/^\n{2,}/gm, '\n');
                dest = dest.replace(/\n/gm, nl);

                if (mSrc) {
                    mDest = dest.match(pattern);
                    mSrc.forEach(function(match, index) {
                        dest = dest.replace(mDest[index], match);
                    });
                }

                grunt.file.write(file, dest);
            });
        });
};