what is the lexical environment of a function argument?

Question

Javascript supports First Class Functions, in which case we can pass the function as an argument. An anonymous function that is defined inside an argument list of another functi

Answer 1

Calling an IIFE is effectively the same as first assigning the function to a variable, then then calling the function through that variable; as with any other use of anonymous functions, it's just a shortcut that avoids giving a name to the function. So:

(function(p1,p2){
   p2(p1);
})(true, function(p1){  // an anonymous function passed as an argument.
   m = 3;
   if(p1){...}
});

is equivalent to:

var temp = function(p1,p2){
   p2(p1);
};
temp(true, function(p1) {
   m = 3;
   if(p1){...}
});

except for the addition of temp to the outer scope; since this variable doesn't appear anywhere else, it has no effect. The scopes of all other variables are identical in the two scenarios.