By rule, you get zero.
https://www.alaskaair.com/content/mi...er-overview:AA
For flights taken on or after January 1, 2018:
Base miles earned and class of service bonuses on eligible American-operated flights count toward Alaska Airlines elite status.
https://www.alaskaair.com/content/mi...er-overview:JL
Qualify for mileage accrual
Flights must fall within the eligible flight number range below, and your flight must be marketed and operated by Japan Airlines.
In practice, the rules are honored more in the breach than in the observance when both partners are AS partners (though now that AS is less friendly with AA who knows how they'll handle weird partner codeshare variants of partner ticket/AA metal). Save your paper boarding passes and be prepared to mail them in, and you'll get... something maybe. I would probably not argue whatever it is you get because if they go by the published rules, you should get nothing. Feel free to report back.