typescript - TSLint：表达式的类型为“ void”。 单独声明(TSLint: Expression has type `void`. Put it on its own line as a statement)

Question

When I run firebase deploy the CLI app runs the TS compiler and TSLint throws the error shown on the commented line:

(当我运行firebase deploy ，CLI应用程序将运行TS编译器，TSLint会引发注释行上显示的错误：)

express.get("/shopify/callback", async (req: Request, res: Response): Promise<Response|void> => {
 const {shop, code, state} = req.query;

 // parse the cookie string into an array. if state cookie is "", err
 const stateCookie = cookie.parse(req.headers.cookie as string || "").state;
 if (!stateCookie) return res.status(400).send("No state cookie");

 if (state !== stateCookie) return res.status(403).send('Cookie failed verification');

 const {hmac, ...params} = req.query;
 const queryParams = queryString.stringify(params);
 const hash = generateEncryptedHash(queryParams); // ERROR: /home/owner/PhpstormProjects/shopify/projectName/functions/src/index.ts:157:15 - Expression has type `void`. Put it on its own line as a statement.
 if (hash !== hmac) return res.status(400).send("HMAC validation failed");

I don't understand what change it wants, does anyone know how to handle this error?

(我不知道需要什么更改，有人知道如何处理此错误吗？)

Here is the helper function being run on that line:

(这是在该行上运行的辅助函数：)

const generateEncryptedHash = (params: unknown) => {
 if (typeof  SHOPIFY_API_SECRET === "string") {
  crypto.createHmac("sha256", SHOPIFY_API_SECRET).update(params as DataView).digest('hex');
 } else {
  throw Error("during generateEncryptedHash() SHOPIFY_API_SECRET was not a string")
 }
};

The full terminal error output is below:

(完整的终端错误输出如下：)

$ firebase deploy --only functions

=== Deploying to 'projectName'...

i  deploying functions
Running command: npm --prefix "$RESOURCE_DIR" run lint

> functions@ lint /home/owner/PhpstormProjects/shopify/projectName/functions
> tslint --project tsconfig.json


ERROR: /home/owner/PhpstormProjects/shopify/projectName/functions/src/index.ts:157:15 - Expression has type `void`. Put it on its own line as a statement.

npm ERR! code ELIFECYCLE
npm ERR! errno 2
npm ERR! functions@ lint: `tslint --project tsconfig.json`
npm ERR! Exit status 2
npm ERR! 
npm ERR! Failed at the functions@ lint script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/owner/.npm/_logs/2019-12-01T16_46_05_460Z-debug.log

Error: functions predeploy error: Command terminated with non-zero exit code2

  ask by Sean Dezoysa translate from so

Answer 1

You don't return anything from generateEncryptedHash hence the void return type.

(您不会从generateEncryptedHash返回任何内容，因此不会返回void返回类型。)

To compare the string you have to return something from that function.

(要比较字符串，您必须从该函数返回一些内容。)

Like that:

(像那样：)

const generateEncryptedHash = (params: unknown): string => {
 if (typeof SHOPIFY_API_SECRET === "string") {
  return crypto.createHmac("sha256", SHOPIFY_API_SECRET).update(params as DataView).digest('hex');
 } else {
  throw new Error("during generateEncryptedHash() SHOPIFY_API_SECRET was not a string")
 }
};

I'm not sure what DataView is but you can update digest only with a string/ Buffer.

(我不确定什么是DataView ，但是您只能使用字符串/缓冲区更新digest 。)

So you have to use JSON.stringify if the input is an object and that's what you want a hash from, eg .update(JSON.stringify(params))

(因此，如果输入是对象，则必须使用JSON.stringify ，而这正是您想要从中.update(JSON.stringify(params))哈希值的原因，例如.update(JSON.stringify(params)))

UPD: you should set a type for the argument params

(UPD：您应该为参数params设置类型)