Somehow I missed this issue. I have never seen this error, could you possible create a JSFiddle or Plunker with which I can reproduce the issue?

I am getting this one too (rc4).. updating to rc9 to see if it is still happening.

Don't know how to reproduce since it randomly happens.

I removed change tracking and I no longer get this issue. Tested on RC9.

@jmdobry
Hello, I get the error in my application, too. It happens every time when I call record.save() in specific methode.
When I set track: false in the schema, the error doesnt occur.

Uncaught (in promise) TypeError: Cannot read property 'indexOf' of undefined
at Record.descriptor.set [as id] (js-data.js?2812:7181)
at Object.deepMixIn (js-data.js?2812:521)
at postProcess (js-data.js?2812:4395)
at
descriptor.set @ js-data.js?2812:7181
deepMixIn @ js-data.js?2812:521
postProcess @ js-data.js?2812:4395
Promise rejected (async)
_callee4$ @ NewHolidays.vue?8bbd:224
tryCatch @ runtime.js?4a57:65
invoke @ runtime.js?4a57:299
prototype.(anonymous function) @ runtime.js?4a57:117
tryCatch @ runtime.js?4a57:65
maybeInvokeDelegate @ runtime.js?4a57:361
invoke @ runtime.js?4a57:273
prototype.(anonymous function) @ runtime.js?4a57:117
step @ asyncToGenerator.js?7b11:17
(anonymous) @ asyncToGenerator.js?7b11:28
Promise resolved (async)
step @ asyncToGenerator.js?7b11:27
(anonymous) @ asyncToGenerator.js?7b11:28
Promise resolved (async)
step @ asyncToGenerator.js?7b11:27
(anonymous) @ asyncToGenerator.js?7b11:28
Promise resolved (async)
step @ asyncToGenerator.js?7b11:27
(anonymous) @ asyncToGenerator.js?7b11:35
F @ _export.js?90cd:35
(anonymous) @ asyncToGenerator.js?7b11:14
saveAbsentDays @ NewHolidays.vue?8bbd:227
boundFn @ vue.runtime.esm.js?ff9b:188
invoker @ vue.runtime.esm.js?ff9b:1982
Vue.$emit @ vue.runtime.esm.js?ff9b:2492
click @ vuetify.js?dc48:6260
boundFn @ vue.runtime.esm.js?ff9b:188
invoker @ vue.runtime.esm.js?ff9b:1982
fn._withTask.fn._withTask @ vue.runtime.esm.js?ff9b:1780

@BennyAlex Could you create a plunker or stackblitz or jsfiddle or something with code that reproduces the error?

I'm having this issue too. Seems like it happens when there are properties in a newly created model which are undefined (having no default value and don't have been set between creation and saving) and then new values come from the server.

When you make sure you have default values for every property you don't set after creation, everything works.

I think this is a bug. js-data should allow to have empty properties when saving a new model.