Access namespaced javascript object by string name without using eval

Question

I ran into a situation where I need access to a javascript object from the server. The server returns the string name of the function or object and based on other metadata I will evaluate the object differently.

Originally I was evaluating (eval([string])) and everything was fine. Recently I was updating the function to not use eval for security peace of mind, and I ran into an issue with namespaced objects/functions.

Specifically I tried to replace an eval([name]) with a window[name] to access the object via the square bracket syntax from the global object vs eval.

But I ran into a problem with namespaced objects, for example:

var strObjName = 'namespace.serviceArea.function';
// if I do
var obj = eval(strObjName); // works

// but if I do
var obj = window[strObjName]; // doesn't work

Can anyone come up with a good solution to avoid the use of eval with namespaced strings?

Answer 1

You could split on . and resolve each property in turn. This will be fine so long as none of the property names in the string contain a . character:

var strObjName = 'namespace.serviceArea.function';
var parts = strObjName.split(".");
for (var i = 0, len = parts.length, obj = window; i < len; ++i) {
    obj = obj[parts[i]];
}
alert(obj);