The short of it, is that I think batjokes is canon in all, yes all, main continuities. Comics, animated, live action. Simultaneously as a mutual thing, and a one sided thing. Allow me to explain.
Batman and Joker seems like a rediculous pairing in canon. They hate eachother, or at least Batman undeniably despised Joker with every fibre of his being and always has. But I call into question what can qualify as a ship. Obviously it doesn't need to be healthy, half of the ships on the internet aren't, canon or not. It doesn't need to be mutual in theory or in practice. It doesn't need to be traditionally romantic. Nor does it need to be positive (i.e. love). I propose that batjokes is a ship built on what I will call mutual all-consuming obsession.
It's pretty self explanatory, really. Batman and Joker are shown repeatedly, again and again, time after time, to be obsessed with each other to the point of mental illness. Both of them will drop everything they're doing for the other, even when it's fully irrational and destructive. Batman is the most important think in Joker's life, and Joker the most important in Batman's. Hell, Bruce abandoned his own actively dying son that *he himself* had potentially fatally injured, to go run after Joker (*cough* batarang incident *cough*). There is nothing that could ever be more important to Batman than the Joker, and just because it's out of hatred doesn't deminish my point. Batman hates Joker more than he loves his family, and at times more than he values his principles and ideology. Not consciously, but in a subconscious manner. Almost like an addiction, he does it by instinct.
Batman has an obsession with Joker of a negative nature. He despises Joker, wants him dead more than anything despite his unwillingness to kill him. Joker however has a positive obsession with Batman. Not to mean that it's "healthy" or "good" in any way. But to say that he likes Batman. Loves him, even. Batman is the punchline to all his favorite jokes, Batman is his primary source of entertainment.
I'm tied between two main theories.
Joker doesn't care about/can't distinguish between positive and negative attention. He only sees that Batman is obsessed with him to the same degree that he's obsessed with Batman. He doesn't take into account what that obsession stems from.
Or alternatively, he's just kind of a masochist. Maybe he actively prefers a negative obsession. Or maybe he just prefers specifically Bruce's obsession in whatever form he can get it. He got bored of Harley because her obsession built on love felt too plain. It wasn't enough fun, didn't have enough tension, didn't feed him the way he craved. Batman's negative obsession fills all those gaps, leaves him feeling full and satisfied every time. He could never get bored of Batman.
In the end, regardless, Joker couldn't care less *what* the emotion is. As long as it's intense and genuine, it'll get him going.
The irony of these two is that they orbit around each other. Rely on each other. They are foundational to each other's characters and persons. Without Batman, Joker would get bored of being Joker. He would lose interest and quickly just quit. He's a performance artist who only needs an audience of one. An audience of Batman. With Bruce, the jokes don't land the same, he can't get the reactions that he wants, specifically the intensity that he wants. Joker craves the intensity of Batman's hatred. He doesn't give a fuck what Bruce feels about him, just that it's real, it's raw, and it's the strongest emotion Joker's ever seen. Joker hates boredom. He'd lose purpose without Batman.
And Batman, no, he wouldn't outright cease to be without the Joker there, but the Joker is foundational to the architecture of his ideology. And if there's one thing that can compare to Bruce's obsession with the Joker, it's his obsession with his ideology. Joker acts as a pushback, the ultimate test for every boundary Bruce has, which as a result, makes those boundaries easily defineable. Remove the Joker and those boundaries don't have such clear lines anymore. Taking the Joker from the equation threatens the structural integrity of what defines Batman, and by extension Bruce. No, he won't topple immediately, but it would irreparably destabilize everything that makes Batman, Batman.
It's part of why they always come as a set. One just feels wholly incomplete without the other. They need each other in the most unhealthy and bat shit crazy way possible.
