Javascript 导入静态函数/类时尝试导入错误

Javascript 导入静态函数/类时尝试导入错误,javascript,reactjs,Javascript,Reactjs,我在MyTool.js和我的Component.js export class MyTool { constructor(){ } numToBar(num){ if (num == 0) {return 8;} if (num == 1) {return 16;} if (num == 2) {return 24;} if (num == 3) {return 32;} if (num ==

我在
MyTool.js
和我的
Component.js

export class MyTool {
    constructor(){
      
    }
  
    numToBar(num){
      if (num == 0) {return 8;}
      if (num == 1) {return 16;}
      if (num == 2) {return 24;}
      if (num == 3) {return 32;}
      if (num == 4) {return 64;}
      if (num == 5) {return 128;}
      if (num == 6) {return 256;}
      if (num == 7) {return 512;}
    }
    barToNum(bar){
      if (bar == 8) {return 0;}
      if (bar == 16) {return 1;}
      if (bar == 24) {return 2;}
      if (bar == 32) {return 3;}
      if (bar == 64) {return 4;}
      if (bar == 128) {return 5;}
      if (bar == 256) {return 6;}
      if (bar == 512) {return 7;}
    }
}
  
然后将其导入my
Component.js
并用作静态类

import MyTool from './MyTool.js';

MyTool.numToBar(3);
但是有这样的错误

Attempted import error: './MyTool.js' does not contain a default export (imported as 'MyTool').

我应该在哪里修正???

默认值添加到类定义中:

export default class MyTool {
    constructor(){
      
    }
  
    numToBar(num){
      if (num == 0) {return 8;}
      if (num == 1) {return 16;}
      if (num == 2) {return 24;}
      if (num == 3) {return 32;}
      if (num == 4) {return 64;}
      if (num == 5) {return 128;}
      if (num == 6) {return 256;}
      if (num == 7) {return 512;}
    }
    barToNum(bar){
      if (bar == 8) {return 0;}
      if (bar == 16) {return 1;}
      if (bar == 24) {return 2;}
      if (bar == 32) {return 3;}
      if (bar == 64) {return 4;}
      if (bar == 128) {return 5;}
      if (bar == 256) {return 6;}
      if (bar == 512) {return 7;}
    }
}

default
添加到类定义中:

export default class MyTool {
    constructor(){
      
    }
  
    numToBar(num){
      if (num == 0) {return 8;}
      if (num == 1) {return 16;}
      if (num == 2) {return 24;}
      if (num == 3) {return 32;}
      if (num == 4) {return 64;}
      if (num == 5) {return 128;}
      if (num == 6) {return 256;}
      if (num == 7) {return 512;}
    }
    barToNum(bar){
      if (bar == 8) {return 0;}
      if (bar == 16) {return 1;}
      if (bar == 24) {return 2;}
      if (bar == 32) {return 3;}
      if (bar == 64) {return 4;}
      if (bar == 128) {return 5;}
      if (bar == 256) {return 6;}
      if (bar == 512) {return 7;}
    }
}

谢谢,我只是错过了
default
,但是出现了另一个错误
TypeError:\u MyTool\u js\u网页包\u IMPORTED\u MODULE\u 21\uuuuu.default.numToBar不是一个函数
啊,它可以工作,我需要在方法名中添加“static”,因为您还没有实例化该类。从
const-tool=new-MyTool()开始;tool.barToNum
Thank you@Nick我使用了static。谢谢,我只是错过了
default
,但是又出现了另一个错误
TypeError:\u MyTool\u js\u网页包\u IMPORTED\u MODULE\u 21\uuuuuuuu。default.numToBar不是一个函数
啊,它可以工作,我需要在方法名中添加“static”,因为你还没有实例化这个类。从
const-tool=new-MyTool()开始;tool.barToNum
谢谢@Nick,不过我使用的是静态的。