Validate Document Update - Change document

[Ronny Berndt]

Hi,

is it possible to change a document before an insert?

I would like to modify all keys of an object to lower.
Is this possible?

My JavaScript function so far is:

function(newDoc, oldDoc, userCtx) {
        var objectKeysToLowerCase = function (origObj) {
            return Object.keys(origObj).reduce(function (newObj, key) {
              var val = origObj[key];
              var newVal = (typeof val === 'object') ? 
objectKeysToLowerCase(val) : val;
              newObj[key.toLowerCase()] = newVal;
              return newObj;
            }, {});
        }
        newDoc = objectKeysToLowerCase(oldDoc);
}

I get the following error message: 

Save failed: Expression does not eval to a function. (function(newDoc, oldDoc, 
userCtx) { var objectKeysToLowerCase = function (origObj) { return 
Object.keys(origObj).reduce(function (newObj, key) { var val = origObj[key]; 
var newVal = (typeof val === 'object') ? objectKeysToLowerCase(val) : val; 
newObj[key.toLowerCase()] = newVal; return newObj; }, {}); } newDoc = 
JSON.stringify(objectKeysToLowerCase(oldDoc)); })