如何使index.ts中的某些行不执行? [英] how to make some lines in index.ts not executed?

问题描述

所以在我的 index.ts 中，我最初有这样的代码

 从"./firestore/triggers/users/users_triggers"中以用户身份导出*；从"./firebase_authentication/triggers/firebase_auth_triggers"中将*导出为auth； 

，然后我的 index.ts 中还有另一个 export ，但是我希望仅在满足某些条件的情况下执行此导出.所以在我的 index.ts 中会像这样

 从"./firestore/triggers/users/users_triggers"中以用户身份导出*；从"./firebase_authentication/triggers/firebase_auth_triggers"中将*导出为auth；const MeetSomeCriteria = true;如果(meetSomeCriteria)返回；//如果符合某些条件，那么我希望下面的代码不会被触发从"./utilities/emulators/http_triggers/for_testing_via_firestore_emulators"中将*导出为实用程序； 

但是如果我这样返回我会出错

那么如何使index.ts中的某些行不执行?

这些导出实用程序实际上是一些仅用于Firebase模拟器的功能.我想避免将这些功能部署到生产中

解决方案

打字稿中没有条件导入或导出.也就是说，你不能写类似的东西

  if(条件)从模块"导入x 

但是您可以像这样解决它

  import *作为"./your/module"中的utilimport；导出const实用程序= MeetSomeCriteria?实用导入: 不明确的; 

so in my index.ts I initially have code like this

export * as users from "./firestore/triggers/users/users_triggers";
export * as auth from "./firebase_authentication/triggers/firebase_auth_triggers";

and then I have another export in my index.ts, but I want this export only executed if it meets some criteria. so in my index.ts will be like this

export * as users from "./firestore/triggers/users/users_triggers";
export * as auth from "./firebase_authentication/triggers/firebase_auth_triggers";

const meetSomeCriteria = true;
if (meetSomeCriteria) return;

// if it meets some criteria, then I expect the code below won't be triggered
export * as utilities from "./utilities/emulators/http_triggers/for_testing_via_firestore_emulators";

but I will have error if I have return like that

so how to make some lines in index.ts not executed?

those export utilities is actually some functions that I will be used only for Firebase Emulators. I want to avoid those functions to be deployed in production

解决方案

There are no conditional imports or exports in typescript. Ie you cannot write something like

if (acondition)
  import x from "module"  

But you can workaround it like this

import * as utilimport from "./your/module";

export const utilities = meetSomeCriteria
   ? utilimport 
   : undefined
   ;

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