The destructuring assignment Syntax is a JavaScript expression that
makes it possible to unpack values from arrays,or properties from
objects,into distinct variables.

示例(ES6)：

var person = {firstname: 'john',lastname: 'doe'};

const firstname = person.firstname;
const lastname = person.lastname;

// same as this
const { firstname,lastname } = person;

您可以在MDN找到更多信息

编辑：对于熟悉Python语言的开发人员来说,与Python解包语法进行比较会很有趣.
Python2.7：

>>> _tuple = (1,2,3)
>>> a,b,c = _tuple
>>> print(a,c)
(1,3)

使用Python3的新功能,如PEP 3132,您还可以执行以下操作：

>>> _range = range(5)
>>> a,*b,c = _range
>>> print(a,c)
0 [1,3] 4

添加了一些示例,因为您已经了解了与其他语言类似的方法,因此您可以更快地掌握JS构思.