场景1

test.js

export const test1 = () => { console.log(1); };
export const test2 = () => { console.log(2); };

index.js

import { test1 } from './test';
console.log(test1);

test2 不会被 sharking

场景2

test.js

import test1 from './test1';
import test2 from './test2';
export {
  test1,
  test2,
};

index.js

import { test1 } from './test';
console.log(test1);

test2 会被sharking

场景3

test.js

export { default as test1 } from './test1';
export { default as test2 } from './test2';

index.js

import { test1 } from './test';
console.log(test1);

test2 会被sharking

老师为啥场景1 test2 不能被sharking，再经过一层引入就可以了