The Node Beginner Book
About
The aim of this document is to get you started with developing applications with Node.js, teaching you everything you need to know about "advanced" JavaScript along the way. It goes way beyond your typical "Hello World" tutorial.
本书致力于教会你如何用Node.js来开发应用，过程中会传授你所有所需的“高级”JavaScript知识。本书绝不是一本“Hello World”的教程。
Status
You are reading the final version of this book, i.e., updates are only done to correct errors or to reflect changes in new versions of Node.js. It was last updated on June 5, 2017.
你正在阅读的已经是本书的最终版。因此，只有当进行错误更正以及针对新版本Node.js的改动进行对应的修正时，才会进行更新。最后一次更新在2017年6月5号.
The code samples in this book are tested to work with both the Long Term Support version 6.10.3 as well as the most current 8.0.0 version of Node.js.
本书中的代码案例都在Node.js 6.10.3版本和最近的8.0.0版本中测试过，可以正确工作。
Intended audience
This document will probably fit best for readers that have a background similar to my own: experienced with at least one object-oriented language like Ruby, Python, PHP or Java, only little experience with JavaScript, and completely new to Node.js.
本书最适合与我有相似技术背景的读者： 至少对一门诸如Ruby、Python、PHP或者Java这样面向对象的语言有一定的经验；对JavaScript处于初学阶段，并且完全是一个Node.js的新手。
Aiming at developers that already have experience with other programming languages means that this document won't cover really basic stuff like data types, variables, control structures and the likes. You already need to know about these to understand this document.
这里指的适合对其他编程语言有一定经验的开发者，意思是说，本书不会对诸如数据类型、变量、控制结构等等之类非常基础的概念作介绍。要读懂本书，这些基础的概念我都默认你已经会了。
However, because functions and objects in JavaScript are different from their counterparts in most other languages, these will be explained in more detail.
然而，本书还是会对JavaScript中的函数和对象作详细介绍，因为它们与其他同类编程语言中的函数和对象有很大的不同。
Structure of this document
Upon finishing this document, you will have created a complete web application which allows the users of this application to view web pages and upload files.
读完本书之后，你将完成一个完整的web应用，该应用允许用户浏览页面以及上传文件。
Which, of course, is not exactly world-changing, but we will go some extra miles and not only create the code that is "just enough" to make these use cases possible, but create a simple, yet complete framework to cleanly separate the different aspects of our application. You will see what I mean in a minute.
当然了，应用本身并没有什么了不起的，相比为了实现该功能书写的代码本身，我们更关注的是如何创建一个框架来对我们应用的不同模块进行干净地剥离。 之后你就会明白我在讲什么意思了。
We will start with looking at how JavaScript development in Node.js is different from JavaScript development in a browser.
本书先从介绍在Node.js环境中进行JavaScript开发和在浏览器环境中进行JavaScript开发的差异开始。
Next, we will stay with the good old tradition of writing a "Hello World" application, which is a most basic Node.js application that "does" something.
紧接着，会带领大家完成一个最传统的“Hello World”应用，这也是最基础的Node.js应用。
Then, we will discuss what kind of "real" application we want to build, dissect the different parts which need to be implemented to assemble this application, and start working on each of these parts step-by-step.
最后，会和大家讨论如何设计我们想要的一个“真正”完整的应用，剖析要完成该应用需要实现的不同模块，并一步一步介绍如何来实现这些模块。
As promised, along the way we will learn about some of the more advanced concepts of JavaScript, how to make use of them, and look at why it makes sense to use these concepts instead of those we know from other programming languages.
可以确保的是，在这过程中，大家会学到JavaScript中一些高级的概念、如何使用它们以及为什么使用这些概念就可以实现而其他编程语言中同类的概念就无法实现。