gistfile1.js

function convertObjectKeyToArray(obj,key) {
  if( obj.hasOwnProperty(key) ) {
		if( Object.prototype.toString.call(obj[key]) === '[object Object]' ) {
			new_array = [];
			for ( objkey in obj[key] ) {
				new_array.push(obj[key][objkey]);
			}
			obj[key] = new_array;
		} else {
			print("{" + obj._id + "} has type " + typeof obj[key]+ " for key: " + key );
		}
	}
	return obj;
}

// Example useage.
db.profiles.find().forEach( function( profile ) {
	new_profile = convertObjectKeyToArray(profile,"INSERT SEARCH KEY");
	if( new_profile !== null ){
		db.profiles.save(new_profile);
	} else {
		print ("{"+profile._id+"} had a problem.");
	}
});