What does () mean in JavaScript -

i'm testing invoked function in javascript. found when running below code in chrome, throws uncaught syntaxerror: unexpected token )

function foo(){     console.log(1); }(); 

i think parser break code 2 parts: function declaration , ();. happen if add 1 between (), turns out won't throw error.

so suppose (1); valid expression, means?

thanks answer.

it immediately-invoked function expression:

(function foo(){     console.log(1); })();  // call function here 

explanation:

suppose create function:

function foo(){         console.log(1); } 

now call function do:

foo() 

now if saw gave function name , called it. can call in same line like:

(function foo(){             console.log(1); })(); 

here article can read.