“Ternary operator” means “operator that takes three things”, like unary and binary operators take one and two things.

In C there is an operator for conditional expressions (an ‘if’ that you can put inside expressions) and it looks like this condition ? trueBranch : falseBranch. It takes three expressions, so it’s a ternary operator.

Except it’s the only ternary operator in C (and most languages, if they have one at all), so instead of calling it something like “conditional operator”, they just call it “the ternary operator”

A ternary is a short hand to assign a value based on a true/false statement

let a; if(isTtrue) a=2 else a=9

Becomes

let a = (isTrue) ? 2 : 9

The joke is that the people in the conversation are kinda dumb

Honestly, it is not worth it and only mildly funny. You didn’t miss anything.

To my deranged Friday afternoon brain, this is the funniest bit