According to the New Jersey instructions:
A Resident of New Jersey is an individual that is domiciled in New Jersey for the tax year or an individual that maintains a permanent home in New Jersey and spends more than 183 days in the state.
A Nonresident of New Jersey is an individual that was not domiciled in New Jersey. The individual did not spend more than 183 days in the state even if a permanent home was maintained. If the individual was domiciled in New Jersey but did not maintain a permanent home in New Jersey and did not spend more than 30 days in New Jersey, they are considered a Nonresident.
A Part-Year Resident is an individual that moved into or out of New Jersey during the tax year. File a resident return and allocate the income, exemptions, deductions, etc. To find more information about how to file a part year New Jersey return, click here.
What if I am a resident and my spouse is not?
If a joint federal return was filed and one spouse is a resident and the other is not, the resident spouse can file a married filing separate state return. If both spouses agree to file a married filing joint return, all of the joint income will be taxed as if they are both residents.
To file separate returns within your account, you can file the federal return and wait for the return to be accepted. Then, change the filing status for the primary taxpayer and file a separate return for the first spouse. The second spouse will need to create a new account and file the separate state return in that account (if required to file).
For more information: