An attempt to create an "else" binding with Knockout. Only supports linear statements, no depth.

ko.else.js

(function(){
    var bindingKey = 'else',
        stack = [],
        
        _if = ko.bindingHandlers.if,
        _init = _if.init
        _update = _if.update;

    ko.bindingHandlers[bindingKey] = 
    {
        init: _init,
        update: _update,
        preprocess: function(val)
        {
            console.log('_ELSE_');
            if(!stack.length) throw new Error("Stray 'else' binding");
            // Negate this sonsa bitch
            var last = stack.pop();
            var v = !last ? 'true' : 'false';
            console.log('else',v, 'Last if value: '+ last);
            return v;
        }
    };
    
    // Hijack the if binding
    ko.bindingHandlers.if.init = function()
    {
        var dataValue = ko.utils.unwrapObservable(arguments[1]()),
            result = _init.apply(this, arguments);
        console.log('if', dataValue);
        stack.push(dataValue);
        return result;
    };
    
    // Virtualize this shit
    ko.expressionRewriting.bindingRewriteValidators[bindingKey] = false;
    ko.virtualElements.allowedBindings[bindingKey] = true;


})();

ko.applyBindings({});