A function can return a function object.

Results

function makeConst1() {
    return function() { return 1; }
}
 
function const1a() { return 1; }
var const1b = function() { return 1; }
var const1c = makeConst1();
 
log(const1a());
log(const1b());
log(const1c());
 
log(makeConst1()());