If I place a self-executing JavaScript function inside a 'normal' function, when is it executed?
function normalFunction() {
var a = 1;
(function() {
var b = 2;
var c = 3;
})();
var d = 4;
}
2 Answers
The IIFE will only be invoked if you call normalFunction. Even though the function block will be parsed at load time, the invocation doesn't happen until the enclosing function runs, and then the IIFE gets called with the empty parameter block - ()
It's almost identical to what would happen if you had written:
function normalFunction() {
var tmp = function() {
...
};
tmp();
}
where clearly tmp() only happens during calls to the enclosing function.
1 Comment
igorGIS
So var b = 2; var c = 3; will executing even if i don't call normalFunction() ?
Where a self executing function is placed has very little to do with how it executes. This function will create 2 local variables with initial values, exit and won't have an effect on the enclosing function scope (other than to waste CPU cycles)
awill be seen in self-executing function.bandcwon't be seen outside self-executing function.