What is this practice called in JavaScript?

Question

When you wrap your JavaScript code in a function like this:

(function(){

  var field = ...;
  function doSomthing(){...
  ...


})();

I noticed that this fixes scoping problems for me on a lot of web pages. What is this practice called?

Answer 1

The pattern is called self-invocation, a self-invoking function. It can create a closure, but that is an effect of the pattern (perhaps the intended effect), not the pattern itself.