To add or update customer fields, please do the following, call the method passing a JSONArray containing a JSONObject:
Customer.assignOrUpdateValueToCustomerFields([{key: "key1", value:"value1"},{key: "key2", value:"value2"}]
,(customer) => {
// Do something
}, (onError) => {
// Log error
})
Otherwise, if you want to eliminate a field, you have to do this with an array of strings containing the name of the fields:
Customer.deleteValuesFromCustomerFields({fieldNames: ["field_to_be_deleted1", "field_to_be_deleted2"]}, (customer) => {
// Do something
}, error => {
// Log error
})