Immediately-Invoked Function Expression (IIFE) in JavaScript
November 21, 2023
1. Syntax for using IIFE
IIFE can be used in the code with different syntaxes.Syntax 1: This is commonly used syntax. We will use it in our examples.
(function(){
//code here
})();
Syntax 2:
(function(){
//code here
}());
Syntax 3: IIFE can also be used with unary operators. We should use these syntaxes only when if function is not returning value.
1.
!function(){
//code here
}();
~function(){
//code here
}();
-function(){
//code here
}();
+function(){
//code here
}()
2. Pass value to IIFE
Now lets us start to work with IIFE. Find the first example which is showing how to pass the parameters to function.
<script>
var a =5, b=10;
(function(arg1, arg2){
var sum = arg1 + arg2;
alert(sum);// Output will be 15
})(a, b);
</script>
3. Return value from IIFE
Find the example to get return value using IIFE.
<script>
var message =(function(name){
return 'Your name:' + name;
})('Mahesh');
alert(message); //Output: 'Your name: Mahesh'
</script>
<script>
var message = (function(){
var msg = 'Default Message';
return {
getMsg: function(){
return msg;
},
setMsg: function(data){
msg = data;
}
};
})();
alert(message.getMsg());// Output: Default Message
message.setMsg('Hello World!');
alert(message.getMsg());// Output: Hello World!
</script>
