Javascript Concepts Functions Related

• Global Scope
• Local Scope

var greeting='Welcome to blog';
(function(){
  console.log(greeting); //Output: Welcome to blog
})();

consider above code greeting variable should be global scope, it can access inside the function,

(function(){var greeting = 'Welcome to blog';
  console.log(greeting); //Output: Welcome to blog
})();console.log(greeting); //Output:Reference-Error greeting not defined

https://medium.com/@madasamy/15-javascript-concepts-that-every-nodejs-programmer-must-to-know-6894f5157cb7