And what makes it unconstitutional is its requirement that others states enter the agreement with NJ.
If NJ wanted to pass a law that elimiated voting by citizens for president and automatically instructed its electors to vote for the national popular vote winner that would be 100% constitutional.
This will save New Jersey quite a lot of money over the long haul. They won’t need to police the polls to make sure their elections are particularly honest, because the electoral votes go on the basis of results elsewhere anyway. It will also save the cost of reinterring all the corpses they normally advance to the polling stations a few times and then have to bury again. I suppose there could be a circumstance where the New Jersey vote actually might matter. In such a case, it could be subtly sold to the highest bidder, or exchanged for carbon credits, contraband, a decent IA football team, or what have you.