以下 CoffeeScript：greet = -> "This is an example of a function"編譯時生成以下 JavaScript 代碼：(function() {  var greet;    greet = function() {    return "This is an example of a function";  };}).call(this);我的問題是，為什么 JavaScript 不創建像這樣的單個函數：(var greet = function() {    return "This is an example of a function"};}).call(this);