1.什么是nodejs
1.（javascript跑在机器端，服务端）Javascript on the machine
2.（跑在谷歌v8引擎上）A runtime for Google Chrome's V8 Javascript engine
2.nodejs的使用
1.构建工具（gulp，webpack都要依赖nodejs）Build Tools and Utilities
2.（web应用，web服务端）Web Applications / Web Services
3.nodejs擅长做什么
1.轻量级到大型应用 Lightweight Applications all the way up to very large
2.高并发性 High Concurrency
3.异步 Asyncronous Actions/Requests/non-blocking
4.实时 Realtime Communication
5.同构应用Isomorphic Applications - shared code between server and client