在 NodeJS 中“需要”一个模块时，const 和 var 之间是否存在效率差异
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原文地址: http://stackoverflow.com/questions/23483926/
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Is there an efficiency difference between const vs var while 'requiring' a module in NodeJS
提问by Hugo
I was reading the documentation for https://github.com/rvagg/bland I noticed that, in the examples, they use constto require a module and this made me wonder: is this a good practice? I mean, to me, this looked as a good idea.
我正在阅读https://github.com/rvagg/bl的文档，我注意到，在示例中，他们使用const来要求一个模块，这让我想知道：这是一个好习惯吗？我的意思是，对我来说，这看起来是个好主意。
A direct example from the link above is:
上面链接中的一个直接示例是：
const BufferList = require('bl')
var bl = new BufferList()
bl.append(new Buffer('abcd'))
bl.append(new Buffer('efg'))
/*...*/
I also noticed the lack the semicolons in the example but well, that has been discussed elsewhere thoroughly.
我还注意到示例中缺少分号，但是，这已经在其他地方进行了彻底的讨论。
采纳答案by helpermethod
The constmakes perfect sense here:
在const这里很有意义：
- It documents that the
objectreference is not going to change. - It has block scope (same as
let) which also makes sense.
- 它记录了
对象引用不会改变。 - 它具有块作用域（与 相同
let），这也很有意义。
Other than that it comes down to personal preference (using var, letor const)
除此之外，它归结为个人喜好（使用var,let或const）
