Handlebars ifTest helper. Allows for javascript condition evaluations. http://jsfiddle.net/YsteK/

gistfile1.txt

Handlebars.registerHelper('ifTest', function(expression, options) {

    var evalStr = '',
        context = [options.data, options.hash];

    if(Object.prototype.toString.call(this) == '[object Object]') {
        context.push(this);
    } else {
        context.push({ that: this });
    }

    for(var x = 0; x < context.length; x++) {
        for(var key in context[x]) {
            evalStr += 'var ' + key + '=' + JSON.stringify(context[x][key]) + ';';
        }
    }

    evalStr += expression.replace(/@/g, '').replace(/this/g, 'that');

    try {
        if(!eval(evalStr)) {
            return options.inverse(this);
        } else {
            return options.fn(this);
        }
    } catch(e) {
        console.error(e + "\n\nThe variable may be outside of this context. Did you forget to add it to the hash? i.e. {{#ifTest 'obj > 1' obj=../obj}}");
    }

});