require modular syntax

node.js环境中的全局函数：require  

front-endjs文件用import

The backend runtime introduces a third partyjs文件 就用require()也可以用import(es6语法)

node.js中有3种模块

====>内置模块===>核心模块【node.jsIt is configured during installation】

var fs=require("fs")

====>第三方模块  【下载后使用】npm I 模块名

var mime=require("mime")

====>自己定义的模块

var mytool=require("mytool")

 

举例：

利用requireImport an own modulemytool,然后调用mytool模块中的tool函数

注意：Fill in the correct path,The suffix name is best written

代码：

var mytool=require("./mytool.js")

mytool.tool()

 

 

新建一个mytool.js在里面导入 what we want to calltool函数

代码：

module.exports={

     tool(){

         console.log(6666)

    }

}

 

运行代码

require是导出,exports是导入

注意要和ES6in the import syntax to distinguish yo！

ES6===>export default{}

node.js====>module.exports={}

The difference between the three modules：

The built-in modules can be used directly without downloading in advance.Both built-in modules and third-party modules need to be downloaded,Otherwise, the small black window will report an error during runtime,Says the module is not found.When the third-party magic module is imported, fill in the required importjs文件的路径.

require（“fs”）Where to look for files？

去当前项目中的node_modules文件中找fs文件夹中的package.json中mainThe path corresponding to the field is then imported;没有就去nodeIt is also found in the global installation package path in the installation packagepackage.json中mainThe path corresponding to the field is then imported;如果还是没找到,It will go to the core library to show off and find it,If you still can't find it, you will get an error

流程：

1. 当前项目的node_modules文件夹
2. in the global installation packagenode_global文件夹===>node_modules文件夹
3. in the global installation packagenode_modules文件夹===>npm===>node_modules文件夹[核心库]