@darrene Funny, but I had to change the config to remove the square brackets and replace them with curly brackets around the config parameters to get the config.js file to be accepted:
{
module: 'MMM-fitbit',
position: 'top_center',
**config: {**
credentials: {
client_id: <client_id>,
client_secret: <client_secret>,
},
resources: [
'steps',
'floors',
'caloriesOut',
'distance',
'activeMinutes',
'sleep',
'heart'
],
update_interval: 60
**}**
},