wrap.error.js

function handleError(func){
    return new Proxy(func,{
        apply:function(origionalFunction,scope,arguments){
            var result;
            try{
                result = origionalFunction.apply(scope,arguments);
            }catch(e){
                result = e;
            }finally{
                return result;
            }
        }
    });
}

x.is.after.w.js

function crafty(a){
    if(typeof a === 'string'){
        throw 'we cant have '+a;
    }else{
        return a + a;
    }
}
var notSoCrafty = handleError(crafty);