//
var test1 = function(param){
//do something
};//
var test2 = function(){
function test2(param){
//do something
}
return test2;
}();
//
var test1 = function(param){
//do something
};//
var test2 = function(){
function test2(param){
//do something
}
return test2;
}();if you want to ask which one is good, you can only say the first one. Because example 2 is a completely meaningless example, you may want to compare
//
function(){
function test2(param){
//do something
}
test2()
}(); this avoids contaminating functions with the same name in the scope.
if you are comparing the code I am talking about, it only depends on whether you need to avoid it. If necessary, use example 2 (such as plug-ins you write for others to avoid pollution), and if you don't need (all code that you can control), use example 1.
2 has an extra internal scope than 1
simply returns a function 1 well
you have to do complex operations before returning and you don't want to pollute global scope 2
var test2 = function(){
var a = 10;
function test3(n){
return n+1;
}
function test2(b){
return a+test3(b);
}
return test2;
}(); to put it simply, test2 has a scope that only it can access;
give an example of
a(1) //
function a (i){ ... }
a(2) //
b(1) //
var b = function (i){ ... }
b(2) //
//...
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