JavaScript 数组大括号与方括号
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JavaScript arrays braces vs brackets
提问by Pinkie
What is the difference between each of the following array definitions.
以下每个数组定义之间有什么区别。
var myArray = [];
var myArray = {};
var myArray = new Array();
回答by johusman
The first and third are equivalent and create a new array. The second creates a new empty object, not an array.
第一个和第三个是等效的，并创建一个新数组。第二个创建一个新的空对象，而不是一个数组。
var myArray = []; //create a new array
var myArray = {}; //creates **a new empty object**
var myArray = new Array(); //create a new array
回答by leepowers
var myObject = {};is equivalent to var myObject = new Object();
var myObject = {};相当于 var myObject = new Object();
So, the second example is not an Arraybut a general Object.
因此，第二个示例不是 anArray而是一般Object.
This can get confusing as Arrayis a class and Objectis a class - more precisely Arrayis a sub-class of Object. So, by and large, Objectsemantics are applicable to an Array:
这可能会让人感到困惑，因为它Array是一个类并且Object是一个类 - 更准确地说Array是Object. 因此，总的来说，Object语义适用于Array：
var o = [];
o.push('element1');
o.push('element2');
o['property1'] = 'property value'; // define a custom property.
console.log(o.property1);
console.log(o.length); // Outputs '2' as we've only push()'ed two elements onto the Array
