Node. js loads the module using the require of function

Detailed instructions are written in the notes, here is not wordy, the partners see their own details, do not as the air.

/* in node In the , You can use require() Function to load the module .

 * require The function takes an argument , Parameter values can have the filename of the module with the full path , It can also be the module name . When using node When a module is provided in , in require The function simply specifies the module name .

 * */

//Create a page 2.js; The code is 

var name=" Think think Dr. ";

exports.name=name;

//Create a page 1.js; The code is 

var two=require("./2.js");

console.log(two.name);

//Output result: si si doctor < br / >
/*

 *  in node All script files are a module file , so 1.js Also a module file , Also because the file is passed in a command line window node The command is run directly , So in node The module file is defined as the main module of the application 

 *  The following method can be used to detect whether the current module is the main module 

 * */

if(module===require.main){

    console.log(" The current module is the main module ");

}

//Output result: when the current module main module 

//2. Js code 

var name=" Think think Dr. ";

console.log(name);

exports.name=name;

//1. Js code :

var two=require("./2.js");

var two=require("./2.js");

//
 
 
 

/*require.resolve(str)

 *  in node In the , You can use this function to query the file name of a module file with the full absolute path .

 * */

var url=require.resolve("./2");

console.log(url);

//Output :E: nodegys2. Js 

/*require.cache

 *  in node In the , This property represents the cache for all loaded modules .

 * */

var two=require("./2.js");

var cache=require.cache;

console.log(cache);

/* The output :

 * { 'E:\node\gys\1.js':

 { id: '.',

 exports: {},

 parent: null,

 filename: 'E:\node\gys\1.js',

 loaded: false,

 children: [ [Object] ],

 paths:

 [ 'E:\node\gys\node_modules',

 'E:\node\node_modules',

 'E:\node_modules' ] },

 'E:\node\gys\2.js':

 { id: 'E:\node\gys\2.js',

 exports: { name: ' Think think Dr. ' },

 parent:

 { id: '.',

 exports: {},

 parent: null,

 filename: 'E:\node\gys\1.js',

 loaded: false,

 children: [Object],

 paths: [Object] },

 filename: 'E:\node\gys\2.js',

 loaded: true,

 children: [],

 paths:

 [ 'E:\node\gys\node_modules',

 'E:\node\node_modules',

 'E:\node_modules' ] } }

 * */

//2. Js code 

var name=" Think think Dr. ";

console.log(name);

//1. Js code 

//When a module object cached in the cache is deleted using the delete keyword, the code in the module is rerun the next time the module is loaded
var two=require("./2.js");

var two1=require("./2.js");

console.log(" Delete the former ")

delete require.cache[require.resolve("./2.js")];

console.log(" After deleting ");

var two2=require("./2.js");

/*

 *  The output :

 *  Think think Dr. 

 *  Delete the former 

 *  After deleting 

 *  Think think Dr. 

 * */

Children whether to understand the use of node require() function, this article is their own understanding of some, if there is an omission, please correct.