在node中import from引入的文件要跟.js后缀，但是webapck不用？

Question

//a.js
let b=333;
export {b};


//index.js
import {b} from './a'


//终端
node index.js

//终端提示
Error [ERR_MODULE_NOT_FOUND]: Cannot find module 'E:\ThousandPhone\study\123\a' imported from E:\ThousandPhone\study\123\index.js
Did you mean to import ../a.js?
    at finalizeResolution (internal/modules/esm/resolve.js:259:11)
    at moduleResolve (internal/modules/esm/resolve.js:636:10)
    at Loader.defaultResolve [as _resolve] (internal/modules/esm/resolve.js:726:11)    
    at Loader.resolve (internal/modules/esm/loader.js:97:40)
    at Loader.getModuleJob (internal/modules/esm/loader.js:243:28)
    at ModuleWrap.<anonymous> (internal/modules/esm/module_job.js:47:40)
    at link (internal/modules/esm/module_job.js:46:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}

from后面改成'./a.js'就能打印b,有办法像webpack那样不用加后缀直接'./a'就执行嘛？

Answer 1

webpack有一个配置项叫做resolve.extensions。在导入语句没带文件后缀时，会根据它的配置带上后缀后去尝试询问文件是否存在。