Nunjucks

A rich and powerful templating language for JavaScript.

https://mozilla.github.io/nunjucks/

var nunjucks = require('nunjucks');
 
var MyLoader = nunjucks.Loader.extend({
    async: true,
    getSource: function(name, callback) {
        var res = '...';
        callback(err, res);
    }
});
 
var env = new nunjucks.Environment(new MyLoader(), {autoescape: true}); // !
 
function CustomExtension(cb) {
    this.tags = ['docs'];
 
    this.parse = function(parser, nodes, lexer) {
        var tok = parser.nextToken();
        var args = parser.parseSignature(null, true);
        parser.nextToken();
        var body = parser.parseUntilBlocks('enddocs');
        parser.advanceAfterBlockEnd();
        return new nodes.CallExtensionAsync(this, 'run', args, [body], cb);
    };
 
    this.run = function(context, args, body, cb) {
        var res = env.filters.safe(args + ':' + body()); // prevent escape
        cb(null, res);
    };
}    
env.addExtension('CustomExtension', new CustomExtension());
 
env.renderString('{% docs "<TEST>" %}"OK"{% enddocs %}', console.log);