Found this code back in jQuery 1.9.1. Checked again, and t is still here in jQuery 3.1.0. Suppose it is just in case the values of true and false ever change 😃

Assume nothing!
Question everything!

but if the values of true and false change, these would return those new values? xD

@Swifticus Or do you mean "query everything"?

@StefanH I don't know anything about JS, but is it possible that it's for when you want to pass a function as an argument, but you always want it to return true or false in a corner case?

In languages like C, it is good practice to typedef commonly used native types. For example, instead of using "unsigned long", I might typedef that to "ULONG" and prefer to use that as my data type.

The reason is for portability and to future-proof your code. If a native type doesn't use the same number of bits of memory on two different systems, or if a future compiler update somehow breaks previously-assumed truths about a native type, your whole program can easily be fixed by simply resolving the issue in the typedef.

I realize that jQuery is nowhere near on the level of something like C, and I also realize that booleans are a fairly simple "type" to process...but this smells similar to me.

I think it's for minification purpose.

return a(); is shorter than return false();

I'd it's so that those can be passed as callback functions.

They are used for assignments that need a function. For example:
this.isDefaultPrevented = returnTrue;
isDefaultPrevented is a function so it needs a function that returns true as the default functionality.

What wouldcyou say about 'function(x) { return x;}'? Looks even sillier, yet it isn't.

@icemad bet they could always return 1, 0, pr and of the other bool equivalents

@icemad good point, never thought about that.