What is (function e(t,n,r){ ...}) in Javascript? [duplicate]

Question

I am studying the List.js Framework. This is a starting code. If I remove it(even remove the surrounding "()" of function e), Code is not working.

What is this? I think it is already defined in Javascript method.

(function e(t,n,r){
  function s(o,u){
   if(!n[o]){
    if(!t[o]){
    var a=typeof require=="function"&&require;
    if(!u&&a) return a(o,!0);
    if(i)return i(o,!0);
    var f=new Error("Cannot find module '"+o+"'");
    throw f.code="MODULE_NOT_FOUND",f
    }

    var l=n[o]={exports:{}};
    t[o][0].call(l.exports,function(e){
    var n=t[o][1][e];
    return s(n?n:e)
    },l,l.exports,e,t,n,r)
   }

 return n[o].exports
 }

 var i=typeof require=="function"&&require;
 for(var o=0;o<r.length;o++)
 s(r[o]);

 return s
}
)

Answer 1

It is a minified version of javascript (which does not make any actual difference, other than file size, and readability) so really, it is actually very much normal javascript code. However, written without the non compulsory syntax, unneeded whitespace, shorter variable names, all in efforts to reduce file transfer time.