Rest parameters & Spread Operator - https://www.leeboonstra.com/developer/sencha-ecmascript-2015/

es2015-spreadoperator.js

//ES2015 spread operator
var logTech = function(...spread){
  //This looks much nicer. Has better performance.
  //and contains a true Array.

  console.log(spread); // Array [ "extjs", "javascript", "html5" ]
}

logTech("extjs", "javascript", "html5");

es5-arguments.js

//ES5 function arguments
var logTech = function(){
  console.log(arguments); // { Arguments: 5 more... }
  
  //Although it looks like an array, it’s not a real array. It's an object.
  //So you would do something like this:
  
  var args = Array.prototype.slice.call(arguments, 0);
  
  console.log(args); // Array [ "extjs", "javascript", "html5" ]
}

logTech("extjs", "javascript", "html5");