Simple iteration tag for swig template

swigTag.js

/*
checkout this 
http://paularmstrong.github.io/swig/docs/#tags-custom

setup like below 
// set template engine 
var swig = require('swig');
var swigFilter = require('./swigFilter');
var swigTag = require('./swigTag');
 
app.engine('html', swig.renderFile);
swig.setFilter('substring', swigFilter.substring);
swig.setFilter('printDate', swigFilter.printDate);
swig.setTag('iterate', swigTag.iterate.parse, swigTag.iterate.compile, swigTag.iterate.ends);
swig.setDefaults({
    cache: false   // default 'memory'
});

use : 
{% set stYear = 1950 %}
{% set edYear = 1999 %}
{% iterate item from stYear to edYear %}
<option value="{{ item }}">{{ item }}</option>
{% enditerate %}
*/

exports.iterate = {
    parse : function (str, line, parser, types, stack) {
        var nameSet;
        parser.on(types.NUMBER, function (token) {
            throw new Error('Unexpected number "' + token.match + '" on line ' + line + '.');
        });
        parser.on(types.VAR, function (token) {
            if (token.match === 'from' || token.match === 'to') {
                return;
            }
            nameSet = token.match;
            this.out.push(
                // Prevent the set from spilling into global scope
                '_ctx.' + nameSet
            );
        });

        return true;
    },
    compile: function (compiler, args, content, parents, options, blockName) {
        var output =[
            '(function () {\n',
            '  var __iterFrom = ' + args[1] + ';\n',
            '  var __iterTo = ' + args[2] + ';\n',
            '  for (var i = Number(__iterFrom); i <= Number(__iterTo); i++) {\n',
            '    ' + args[0] + ' = i;\n',
            '    ' + compiler(content),
            '  }\n',
            '})();\n'
        ].join('');

        return output;
    },
    ends: true
};