1-1 NodeJS

What is? Node?

First of all, we need to correct an idea ,node Not a background language . that node What is it? ？
node Is based on V8 engine （ That is, the engine of Google browser ） Rendering JS Tools or environments .
Use node The following preparation steps are required before ：
1. install node
2. take JS Put the code in node In the implementation of

install node

Official website address ：https://nodejs.org/zh-cn/
It is recommended that novices download the stable version
After a fool's installation , The computer automatically installed successfully npm(js Module management tool ).
be based on npm You can install and download js modular .
js Encapsulation means that all modules are good , A bag that can be directly retrieved or used by others .

How to be in node Rendering and parsing in js

The first pattern ：
REPL Pattern （Read-Evaluate-print-Loop, Input - evaluation - Output - loop ）
This mode is very similar to the browser console , It's just that this is implemented in node：

ctrl+c You can execute the end command

Second mode ：
Based on the direct Node To execute js
（1） Execute directly through the command window ：（DOS window & A terminal window ）
Find the file directory , Directly through node xxx.js Can be executed directly js file

（2） Execute directly in the development tool （ I used it here Hbuilder）.