When they bury Kristal Bayron-Nieves, dead at 19 in an East Harlem fast-food-joint robbery-murder, will Manhattan’s new DA, Alvin Bragg, show up? That’s doubtful. But he should.

For how better to feel the pain of a family deprived of a bright and promising daughter, a woman who didn’t want to work the night shift at Burger King because she felt it was too dangerous — but who did anyway because her mother convinced her it was the responsible thing to do?

Can you possibly imagine the terror the young lady felt when her fears became her reality — when the man standing at the counter produced a pistol and demanded cash?

More to the point, can Bragg? There’s no reason to think so.

Nieves handed over $100 or so, but the man shot her anyway, pistol-whipped a customer and then punched the store manager on the way out the door. He was in the wind Monday afternoon; for how long is anybody’s guess.

But this much is a safe bet: When (if?) the cops track him down, he will in some way turn out to have been a beneficiary of New York’s insane criminal-justice “reforms” of the past two years. People usually don’t gun down teen-aged restaurant cashiers as a first offense.

Indeed, if only the perp hadn’t pressed the trigger — that is, if only he had just waved a loaded gun — he’d be a prime candidate for leniency under Bragg’s recently promulgated new rules for prosecuting crime in New York City’s most prominent borough.

Or not prosecuting it, as appears to be Bragg’s plan.

In a staff memo made public last week, Bragg said armed robbery generally will be charged as a felony only if someone is hurt. That is, only if the gun goes off. Never mind the lethal potential of loaded illegal guns; never mind the gut-churning terror felt by victims of armed offenders; and never mind the socially demoralizing effect of a pro-criminal district attorney.

Based on his own policy directive, Bragg’s principal worry is the negative impact of effective law-enforcement on criminals. “Carceral” sentencing — the word is prog-speak for prison — is life changing, he says, and thus as a rule is to be avoided irrespective of consequences.

He’s correct about adverse effect, of course, but that’s an odd worry for a district attorney — who traditionally is more concerned with the negative impact of crime on law-abiding citizens. Such as Bayron-Nieves, a young lady smart enough to recognize the dangers of the night shift — she told of having to step around drugged-out vagrants to get to work — but stand up enough to do it anyway.

Her tragedy won’t be lost on others in her circumstances, of course. Many will respond accordingly and simply stay home — further diminishing hope in a hard-pressed neighborhood and generally accelerating an obvious downward spiral.

The same can be said of Manhattan — and, indeed, all of New York. Each fatal shooting, all the stabbings, every subway shoving, the blatantly public drug shooting galleries and the vagrant-plagued public spaces all contribute to a not-unwarranted sense of a city in perilous decline.

Alvin Bragg and his wrong-headed policies stand only to make matters worse. He needs a lesson in how life is lived in post-Bill de Blasio New York — and, again, a good place to start would be by attending Bayron-Nieves’ funeral.

Bet he doesn’t dare.

E-mail: bob@bobmcmanus.nyc