Grunt task to convert underscore templates to jade

underscore-to-jade.js

'use strict';

module.exports = function(grunt) {
    var cheerio = require("cheerio"),
        _ = require("underscore"),
        jadeWrapIndent = function(renderedContent, indentLevel) {
            var indentation=[];
            for(var i=0;i<indentLevel;i++){
                indentation.push('  ');
            }
            return indentation.join('') + renderedContent;
        },
        jadeComment = function(content) {
            return '// ' + content;
        },
        jadePipedText = function(content) {
            return '| ' + content;
        },
        jadeTag = function(tag, attribs, content) {
            var attrStr='', tagAddition='', renderedTag='', attrs = [];
            _(attribs).each(function(val, key){
                if(key=='class') {
                    val && (tagAddition += '.' + val.split(' ').join('.'));
                } else if( key=='id') {
                    tagAddition += '#' + val;
                } else {
                    attrs.push(key + '=\"' + val + '\"');
                }
            });
            attrStr = attrs.join(', ');
            renderedTag += (tag=='div'?'':tag) + tagAddition + (attrStr ?
                '('+ attrStr + ')' : '');
            return renderedTag;
        },
        process = function(tagTree, indentLevel, list) {
            //grunt.log.writeln(tagTree.name);
            list.push(jadeWrapIndent(
                jadeTag(tagTree.name, tagTree.attribs,
                        tagTree.data), indentLevel));
            tagTree.children.forEach(function(value, index){
                //grunt.log.writeln(value.type, Object.keys(value), value.data);
                if(value.type==='tag'){
                    process(value, indentLevel+1, list);
                } else if( value.type=='text'){
                    if(value.data.trim())
                        list.push(jadeWrapIndent(jadePipedText(
                            value.data.trim()), indentLevel+1));
                } else if(value.type=='comment') {
                    list.push(jadeWrapIndent(jadeComment(value.data),
                                             indentLevel+1));
                }
            });
            return list;
        };

    grunt.registerMultiTask('j2j', 'Convert JST templates to jade', function() {
        var self = this;
        this.filesSrc.forEach(function(jst_file){
            grunt.log.writeln('//- ', jst_file);
            var content = grunt.file.read(jst_file),
                compiled = '',
                cleanedContent = content
                    // Variable interpolation syntax
                    .replace(/<%- *([^ ]+) *%>/g, function(all_match, group) {
                        return '#{' + group.replace( /^rc\./, '' ) + '}';
                    })
                    .replace(/<%/g, '<!-- <%')
                    .replace(/%>/g, '%> -->'),
                parsedContent = cheerio.load(cleanedContent);
            parsedContent.root().children().each(function(index, value){
                // grunt.log.writeln(value);
                compiled += process(value, 0, []).join('\n') + '\n';
            });

            // variables assigned to HTML attributes
            compiled = compiled.replace(/\="#{([^}]+)}"/g, function(all, group) {
                return '=' + group;
            }).replace(/\n( *)\| #{([^}]+)}/g, function(all_match, group1, group2) {
                return '\n' + group1 + '= ' + group2;
            }).replace(/\n( *)\/\/ *<% if \( ([^)]+) \) { %>/g, function(all_match, group1, group2) {
                return '\n' + group1 + ' if ' + group2;
            }).replace(/([^a-zA-Z_])rc\./g, '$1')
            .replace(/ +\n/g, '\n');

            grunt.file.write(
                jst_file.replace(/\.html$/,'.jade').replace(/^jst\//, 'jade/'),
                compiled
            );
        }, this);
    });
};