There should be a (perhaps configurable) warning when using undefined variables

[jakub-g]

When I use an undefined variable in a template, hashspace wants to be user-friendly and treats this as an empty string.

That's okay, it's certainly better than to break the whole application, but I think things like this should be logged into the console, because they can hide a developer's bug and it might be tricky to immediately know that in big apps with complex logic. The experience of many projects shows that too much user-friendliness can bite in the least expected moments and make debugging painful.

http://plnkr.co/edit/FNuImk92ug07LxzZU7ue?p=preview

# template mytest()
    <div>
    {let foo = 1}
    <p>Fuu has a value of: {fuu}</p>
    // oh I wanted to use foo, but I was really sloppy when writing that, and I forgot to validate
    </div>
# /template

mytest().render("output");

[b-laporte]

Well today you have 2 solutions:

• TDD (!)
• or use {log}

Having said that I am not against a specific option - but I guess it should be scoped, like {let} - otherwise you may have many logs in a large application, which would result in painful troubleshooting..

[piuccio]

In this specific case, I'd prefer to have an option to throw an error!

var foo = 1;
console.log(fuu);
// this throws a ReferenceError

But in general the current behavior seems the best option, finding these errors is responsibility of a linter, not the template engine.