Determine if current user is a member of Group via CSOM(JavaScript) in SharePoint 2010/2013

SP.IsCurrentUserMemberOfGroup.Example.js

//Usage
function IsCurrentUserWithContributePerms() 
{
  IsCurrentUserMemberOfGroup("Members", function (isCurrentUserInGroup) {
    if(isCurrentUserInGroup)
    {
        // The current user is in the [Members] group
    }
  });

}
ExecuteOrDelayUntilScriptLoaded(IsCurrentUserWithContributePerms, 'SP.js');

SP.IsCurrentUserMemberOfGroup.js

function IsCurrentUserMemberOfGroup(groupName, OnComplete) {
 
        var context = new SP.ClientContext.get_current();
        var currentWeb = context.get_web();
 
        var currentUser = context.get_web().get_currentUser();
        context.load(currentUser);
 
        var allGroups = currentWeb.get_siteGroups();
        context.load(allGroups);
 
        var group = allGroups.getByName(groupName);
        context.load(group);
        
        var groupUsers = group.get_users();
        context.load(groupUsers);
 
        context.executeQueryAsync(
                function(sender, args) {
                   var userInGroup = IsUserInGroup(currentUser,group);         
                   OnComplete(userInGroup);
                },
                function OnFailure(sender, args) {
                   OnComplete(false);
                }
        );
        
        function IsUserInGroup(user,group)
        {
            var groupUsers = group.get_users();
            var userInGroup = false;
            var groupUserEnumerator = groupUsers.getEnumerator();
            while (groupUserEnumerator.moveNext()) {
                var groupUser = groupUserEnumerator.get_current();
                if (groupUser.get_id() == user.get_id()) {
                    userInGroup = true;
                    break;
                }
            }
            return userInGroup;
        }
}

The only solution for this problem that I can think of is to create a list item with a 'User' column set to the group name. Then query the list with a CAML query that specifies that the current user should be a member of the group in that column. If it comes back in the result, then they're a member.

This is obviously slow but with some caching, maybe it'd be okay. It's the only thing I can think of. Thoughts?

@Johnycardy That's the exact approach we followed. Replying to a 4-year-old thread as the solution you proposed works elegantly.