从nodejs，es6，typescript方面去弄清楚exports，require，export，import，export=

时间：2020-04-27 17:15:13 阅读：51 评论：0 收藏：0 [点我收藏+]

标签：children ret 快捷方式不能 enc 支持 list 关系 closed

nodejs中的module.exports 与 require

list.js

exports.f = function(f){}
module.exports.hello = "hello"

console.log(module)

index.js

const a = require(‘./list‘)
console.log(a)

结果：

Module {
  id: ‘D:\\DEV\\nodejs\\list.js‘,
  exports: { f: [Function], hello: ‘hello‘ },
  parent:
   Module {
     id: ‘.‘,
     exports: {},
     parent: null,
     filename: ‘D:\\DEV\\nodejs\\index.js‘,
     loaded: false,
     children: [ [Circular] ],
     paths:
      [ ‘D:\\DEV\\nodejs\\node_modules‘,
        ‘D:\\DEV\\node_modules‘,
        ‘D:\\node_modules‘ ] },
  filename: ‘D:\\DEV\\nodejs\\list.js‘,
  loaded: false,
  children: [],
  paths:
   [ ‘D:\\DEV\\nodejs\\node_modules‘,
     ‘D:\\DEV\\node_modules‘,
     ‘D:\\node_modules‘ ] }
{ f: [Function], hello: ‘hello‘ }

View Code

注意：exports快捷方式其实就是exports指向了module.exports。module.exports 可以直接赋值。以上例子a = module.exports。

ES2015中export，import，impot * as xx, export default

导出导入的对应关系如下：

// circle.js

export function area(radius) {
  return Math.PI * radius * radius;
}

export function circumference(radius) {
  return 2 * Math.PI * radius;
}


// main.js

import { area, circumference } from ‘./circle‘;

console.log(‘圆面积：‘ + area(4));
console.log(‘圆周长：‘ + circumference(14));

import * as circle from ‘./circle‘;

console.log(‘圆面积：‘ + circle.area(4));
console.log(‘圆周长：‘ + circle.circumference(14));

export default

// export-default.js
export default function () {
  console.log(‘foo‘);
}

// import-default.js 可以自定义名字
import customName from ‘./export-default‘;
customName(); // ‘foo‘

typescript