简体繁体 English

为什么要将此分配给另一个变量？

[英]why would you assign this to another variable?

原文 2012-04-15 15:45:42 3 1 javascript

At the start of the source code for underscore.js , you see this: 在underscore.js的源代码开头，您会看到以下内容：

var root = this;

var previousUnderscore = root._;

So the question becomes why didnt the author just write: 所以问题就变成了为什么作者不写：

var previousUnderscore = this._;

1 个解决方案

Two reasons, 有两个原因，

Readability, it makes it clearer what the code is doing, what it is referencing. 可读性，它使代码正在做什么，正在引用什么变得更加清晰。 this is very opaque. 这是非常不透明的。
depending on context, this can refer to lots and lots and lots of differnt objects, root may be used in multiple place and will always refer to the correct object. 根据上下文的不同，它可以引用很多很多不同的对象，root可以在多个地方使用，并且始终引用正确的对象。

为什么要为变量分配一个函数而不是声明一个命名函数？ - Why would you assign a function to a variable instead of declaring a named function?

我如何将一个变量分配给另一个变量加上一个常量 - How would I assign a variable to another variable plus a constant

为什么要将全局变量传递给函数？ - Why would you pass a global variable to a function?

为什么要创建一个具有此值的变量 - Why would you create a variable with value this

为什么要为命名变量分配函数声明？ - Why would I assign a function declaration to a named variable?

你应该为变量x分配什么JavaScript值，以便typeof x = = = x是真的？ - What JavaScript value should you assign to a variable x so that typeof x = = = x would be true?

jsp-如何将输入值分配给我以后要使用的另一个变量？ - jsp- how to assign input value into another variable I would like to use later?

为什么要将IIFE分配给变量？ - Why assign an IIFE to a variable?

你为什么要在javascript中使用0> 0？ - Why would you use 0 > 0 in javascript?

为什么我不能使用“ this”将对象中的对象变量分配给JavaScript中该对象中的另一个变量 - Why I cant use “this” to assign a object variable from a object to another variable in that object in JavaScript

暂无

暂无

声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.

相关问题 为什么要为变量分配一个函数而不是声明一个命名函数？ - Why would you assign a function to a variable instead of declaring a named function? 我如何将一个变量分配给另一个变量加上一个常量 - How would I assign a variable to another variable plus a constant 为什么要将全局变量传递给函数？ - Why would you pass a global variable to a function? 为什么要创建一个具有此值的变量 - Why would you create a variable with value this 为什么要为命名变量分配函数声明？ - Why would I assign a function declaration to a named variable? 你应该为变量x分配什么JavaScript值，以便typeof x = = = x是真的？ - What JavaScript value should you assign to a variable x so that typeof x = = = x would be true? jsp-如何将输入值分配给我以后要使用的另一个变量？ - jsp- how to assign input value into another variable I would like to use later? 为什么要将IIFE分配给变量？ - Why assign an IIFE to a variable? 你为什么要在javascript中使用0> 0？ - Why would you use 0 > 0 in javascript? 为什么我不能使用“ this”将对象中的对象变量分配给JavaScript中该对象中的另一个变量 - Why I cant use “this” to assign a object variable from a object to another variable in that object in JavaScript

相关标签

粤ICP备18138465号 © 2020-2024 STACKOOM.COM