CODEWITHSUNDEEP
javascriptanonymous-function
Arshad Rehmani
Arshad Rehmani

Reputation: 2185

When to use automatic function execution

For below piece of code, I am aware that its an automatic function execution code (I saw it being used inJQuery).

var f = function() {

  // function body code
  // ...
  // ...

}();

What I want to understand is its usage.

  1. Under which all scenarios we should prefer to use above syntax?

  2. What are the advantages/benefits do we get by using above syntax?

Upvotes: 2

Views: 82

Answers (1)

Rajaprabhu Aravindasamy
Rajaprabhu Aravindasamy

Reputation: 67207

"Immediately invokable function expression" is the right name for it. And its usages are many, basically it will tightly wrap the scope and will not permit access to its variable to outside scope unless we are intentionally doing it.

And you can build singleton pattern by using it. One of the usages of Singleton pattern is to amend data encapsulation. Like setters and getters.

Possible usage situation:

<script src="someLibrary.js"></script> //And it uses a global variable called x
<script>
  var x = 10; //Now at this situation, 
              //the x belongs to someLibrary will be overridden here.
</script>

So in order to avoid such conflicts, we can use IIFE,

<script>
  (function(){
    var x = 10; 
    .
    .
    //Other codes goes here.
  })();
</script>

Upvotes: 2

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