If you never physically work within New Jersey, then your income is not taxed by New Jersey. It is taxed only by your resident state of Massachusetts.
"With regard to nonresident telecommuters working from home for a New Jersey employer to perform work or services, only the telecommuting employee’s home state taxes the income."
https://www.nj.gov/treasury/taxation/conveniencerulefaq.shtml
But if you sometimes work within NJ, then that portion of your income would be taxable by NJ. In that situation, MA would give you an "other state credit" for the taxes paid to NJ. The credit prevents double taxation, which is prohibited by a U.S. Supreme Court ruling.
If your employer does not withhold MA income tax from your pay, then you must make quarterly estimated tax payments to MA. See this:
https://www.mass.gov/info-details/massachusetts-dor-estimated-tax-payments
**Answers are correct to the best of my ability but do not constitute tax or legal advice.