N.J. Stat. Ann. § 34:11-21

It shall not be lawful for an employer, or his agents, clerks or superintendents, owning or controlling any stores for the sale of general store goods or merchandise in connection with his manufacturing or other business, to attempt to control his employees in the purchase of store goods or supplies at such stores by withholding payment of wages beyond the usual time of payment, whereby the employee would be compelled to purchase supplies at any such stores.