好吧，var x = new Array()与var x =[]在某些特性上是不同的，我只解释其中最有用的两个(在我看来)。

在我解释这些区别之前，我将首先设定一个基础;当我们使用x =[]时，定义了一个数据类型为Array的新变量，它继承了属于数组原型的所有方法，这与扩展一个类非常相似(但不完全相同)。但是，当我们使用x = new Array()时，它会初始化分配给变量x的数组原型的克隆。

现在让我们看看有什么不同

The First Difference is that using new Array(x) where x is an integer, initilizes an array of x undefined values, for example new Array(16) will initialize an array with 16 items all of them are undefined. This is very useful when you asynchronously fill an array of a predefined length. For example (again :) ) let's say you are getting the results of 100 competitiors, and you're receiving them asynchronously from a remote system or db, then you'll need to allocate them in the array according to the rank once you receive each result. In this very rare case you will do something like myArray[result.rank - 1] = result.name, so the rank 1 will be set to the index 0 and so on.

The second difference is that using new Array() as you already know, instanciates a whole new clone of the array prototype and assigns it to your variable, that allows you to do some magic (not recommended btw). This magic is that you can overwrite a specific method of the legacy array methods. So, for example you can set the Array.push method to push the new value to the beginning of the array instead of the end, and you can also add new methods (this is better) to this specific clone of the Array Prototype. That will allow you to define more complex types of arrays throughout your project with your own added methods and use it as a class.

最后一件事，如果你来自极少数关心应用程序处理开销和内存消耗的人(我真的很喜欢)，你永远不会不顾一切地使用新Array():)。

我希望这已经足够解释野兽new Array():)

有关更多信息，下面的页面描述了为什么永远不需要使用new Array()

你永远不需要使用new Object()在 JavaScript。使用对象文字{} 代替。同样，不要使用new Array()， 使用数组文字[] 代替。JavaScript中的数组可以工作 不像Java中的数组，而且 使用类似java的语法 迷惑你。 不使用新数字，新字符串，或 新布尔。这些形式产生 不必要的对象包装。只使用 而是简单的字面量。

还要查看注释——新的Array(length)表单没有任何有用的用途(至少在今天的JavaScript实现中)。

当你初始化没有任何长度的数组时，没有区别。因此var a = [] & var b = new Array()是相同的。

但是如果你初始化数组的长度像var b = new array(1);，它将数组对象的长度设置为1。所以它等价于var b = [];b.length = 1;。

当你使用array_object时，这就会有问题。按下，它在最后一个元素后添加项目并增加长度。

var b = new Array(1);
b.push("hello world");
console.log(b.length); // print 2

vs

var v = [];
a.push("hello world");
console.log(b.length); // print 1

好吧，var x = new Array()与var x =[]在某些特性上是不同的，我只解释其中最有用的两个(在我看来)。

在我解释这些区别之前，我将首先设定一个基础;当我们使用x =[]时，定义了一个数据类型为Array的新变量，它继承了属于数组原型的所有方法，这与扩展一个类非常相似(但不完全相同)。但是，当我们使用x = new Array()时，它会初始化分配给变量x的数组原型的克隆。

现在让我们看看有什么不同

The First Difference is that using new Array(x) where x is an integer, initilizes an array of x undefined values, for example new Array(16) will initialize an array with 16 items all of them are undefined. This is very useful when you asynchronously fill an array of a predefined length. For example (again :) ) let's say you are getting the results of 100 competitiors, and you're receiving them asynchronously from a remote system or db, then you'll need to allocate them in the array according to the rank once you receive each result. In this very rare case you will do something like myArray[result.rank - 1] = result.name, so the rank 1 will be set to the index 0 and so on.

The second difference is that using new Array() as you already know, instanciates a whole new clone of the array prototype and assigns it to your variable, that allows you to do some magic (not recommended btw). This magic is that you can overwrite a specific method of the legacy array methods. So, for example you can set the Array.push method to push the new value to the beginning of the array instead of the end, and you can also add new methods (this is better) to this specific clone of the Array Prototype. That will allow you to define more complex types of arrays throughout your project with your own added methods and use it as a class.

最后一件事，如果你来自极少数关心应用程序处理开销和内存消耗的人(我真的很喜欢)，你永远不会不顾一切地使用新Array():)。

我希望这已经足够解释野兽new Array():)

我在使用[]时出现了奇怪的行为。

我们有模型“类”，字段初始化为一些值。例如:

require([
  "dojo/_base/declare",
  "dijit/_WidgetBase",
], function(declare, parser, ready, _WidgetBase){

   declare("MyWidget", [_WidgetBase], {
     field1: [],
     field2: "",
     function1: function(),
     function2: function()
   });    
});

我发现当字段用[]初始化时，它将被所有Model对象共享。对其中一项进行更改会影响所有其他项。

用new Array()初始化它们时不会发生这种情况。对象的初始化也是一样({}vs new Object())

TBH我不确定这是否是我们使用的框架(Dojo)的问题

在使用承诺时，我发现了一个不同。在使用承诺数组(例如arr，初始化为arr=[])时，在Promise.all(arr)中得到一个错误。而当声明为arr = Array()时，没有得到编译问题。希望这能有所帮助。