Whether the modification of import and export values by ES6 and commonjs affects the original module

All say es6 The export of is a reference ,commonjs Export is a copy of value , So I want to test ：

commonjs

commonjs Yes Reference type export ： Modify the exported reference , Will change the value of the module , And modules that reference this module can get the latest value

// a.js
module.exports.x = "default1";
setTimeout(() => {
    
  module.exports.x = 6;
}, 4000);
setInterval(() => {
    
  console.log('a',module.exports);
}, 1000);

// b.js
let a = require("./a.js");
setInterval(() => {
    
  console.log('b',a);
}, 1000);
setTimeout(() => {
    
  a.x = "2";
}, 2000);

The result is ：

a { x: 'default1' }
b { x: 'default1' }
a { x: '2' }
b { x: '2' }
a { x: '2' }
b { x: '2' }
a { x: 6 }
b { x: 6 }

commonjs Export to basic data type ： Invalid external modification （ Will be out of direction ）, Internal modification , Cannot be reflected externally ！

// a.js
module.exports = "default1";
setTimeout(() => {
    
  module.exports = 6;
}, 4000);
setInterval(() => {
    
  console.log('a',module.exports);
}, 1000);

// b.js
let a = require("./a.js");
setInterval(() => {
    
  console.log('b',a);
}, 1000);

The result is ：

a default1
b default1
a default1
b default1
a default1
b default1
a 6
b default1

es6

about es6 Derived Reference type data , Changes anywhere will affect data elsewhere ！

// a.js
let x = {
    name:"default1"};
export let y = {
    name:"default2"};
export default x;
setTimeout(() => {
    
  x.name = "4";
  y.name = "4";
}, 4000);
setInterval(() => console.log("a", x, y), 1000);

// b.js
import x from "./a.js";
import {
     y } from "./a.js";
setInterval(() => console.log("b", x, y), 1000);
setTimeout(() => {
    
  x.name = "2";
  y.name = "2";
}, 2000);

result ：

a {name: 'default1'} {name: 'default2'}
b {name: 'default1'} {name: 'default2'}
a {name: 'default1'} {name: 'default2'}
b {name: 'default1'} {name: 'default2'}
a {name: '2'} {name: '2'}
b {name: '2'} {name: '2'}
a {name: '4'} {name: '4'}
b {name: '4'} {name: '4'}

Replace with basic type data , test result ： The value of the incoming module cannot be changed externally , Because it is introduced by the read-only attribute , However, after internal changes, the latest value can be obtained by external non default Export ！

// a.js
let x = 'default1';
export let y = 'default1';
export default x;
setTimeout(() => {
    
  x = "4";
  y = "4";
}, 4000);
setInterval(() => console.log("a", x, y), 1000);

// b.js
import x from "./a.js";
import {
     y } from "./a.js";
setInterval(() => console.log("b", x, y), 1000);
setTimeout(() => {
    
  x = "2"; //  Report errors ！ Prompt constant cannot be assigned 
  y = "2"; //  Report errors ！ Prompt constant cannot be assigned 
}, 2000);

result ：

a default1 default1
b default1 default1
a default1 default1
b default1 default1
 Wrong report ...
a default1 default1
b default1 default1
a 4 4
b default1 4

summary

---

• Export in module Basic types of data when ,require The method cannot obtain the latest internal data, and modifying the variable value will decouple ,import The data of the module cannot be modified outside the mode （ read-only ）, But the non default export attribute can get the latest internal value .
• Export in module Reference type data when , Both external and internal modifications can be observed ！

---