Node.js：如果传递的数据无效，应该拒绝并显示错误。

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英文:

Node.js: should reject with an error if the passed data is invalid

问题

I'm getting a problem while running the test cases using the node.js application where I'm creating a directory if not exists, writing the json and reading the file.

Here's the Working Demo Link

It's throwing the below error even after handling the error in the code. I didn't get much help from other solutions related to Promise rejection in Stackoverflow. Looking for a working solution. I'm getting the below issue after doing npm test:

  1. should reject with an error if the passed data is invalid:
  3. Uncaught TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Promise
  4.   at TypeError.get (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:385021)
  5.   at EventEmitter.emit (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:143926)
  6.   at process.onGlobalUncaughtException [as _fatalException] (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:363886)
  7.   at triggerUncaughtException (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:42:367400)
  8.   at processPromiseRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:1794051)
  9.   at processTicksAndRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:801887)
  10.   at _0x263935 (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:37:263515)

While doing npm start I'm getting the below problem:

  1. Server running at http://127.0.0.1:3000/
  2. Error: Invalid data
  3.     at writeJSON (file:///home/projects/stackblitz-starters-xzxhal/index.js:70:15)
  4.     at Server.eval (file:///home/projects/stackblitz-starters-xzxhal/index.js:24:15)
  5. TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Promise
  6.     at TypeError.get (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:385021)
  7.     at triggerUncaughtException (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:42:367449)
  8.     at processPromiseRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:1794051)
  9.     at processTicksAndRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:801887)
  10.     at _0x263935 (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:37:263515) {
  11.   code: 'ERR_INVALID_ARG_TYPE'
  12. }

Here's my index.js file code pieces:

  1. const server = http.createServer(async (req, res) => {
  2.     res.statusCode = 200;
  3.     res.setHeader('Content-Type', 'text/plain');
  4.     const dirPath = DIR_PATH + dirs[0];
  5.     const filePath = dirPath + './data.json';
  6.     let createdDirectoryIfNotExists = await createDirectoryIfNotExists(filePath);
  7.     if (createdDirectoryIfNotExists) {
  8.         res.writeHead(200, { 'Content-Type': 'application/json' });
  9.         res.write(writeJSON('./temp', contents));
  10.         res.end();
  11.     }
  12. });
  14. // write json in file
  15. const writeJSON = async (filePath, contents) => {
  16.     try {
  17.         if (contents && typeof contents === "object") {
  18.             const jsonString = JSON.stringify(contents);
  19.             // write file 
  20.             let isWriteFileSynced = fs.writeFileSync(filePath, jsonString, error => {
  21.                 if (error) {
  22.                     console.log(error);
  23.                 } else {
  24.                     return jsonString;
  25.                 }
  26.             })
  27.             if (isWriteFileSynced) {
  28.                 // read file after file is written
  29.                 let isReadFileSynced = fs.readFileSync(filePath, "utf8", (error, jsonString) => {
  30.                     if (error) {
  31.                         return false;
  32.                     } else {
  33.                         return jsonString;
  34.                     }
  35.                 })
  37.                 // if read file, return the jsonString
  38.                 if (isReadFileSynced) {
  39.                     return jsonString;
  40.                 }
  41.             } else {
  42.                 throw new Error("Invalid data");
  43.             }
  44.             return jsonString;
  45.         }
  46.     } catch (error) {
  47.         console.log(error);
  48.         return;
  49.     }
  51. };
  54. // create directory if not exists
  55. const createDirectoryIfNotExists = async (path) => {
  56.     fs.mkdirSync(path, { recursive: true });
  57.     return true;
  58. };

How to solve this issue?

英文:

I'm getting a problem while running the test cases using the node.js application where I'm creating a directory if not exists, writing the json and reading the file.

Here's the Working Demo Link

It's throwing the below error even after handling the error in the code. I didn't get much help from other solutions related to Promise rejection in Stackoverflow. Looking for a working solution. I'm getting the below issue after doing npm test:

  1. should reject with an error if the passed data is invalid:
  3. Uncaught TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Promise
  4.   at TypeError.get (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:385021)
  5.   at EventEmitter.emit (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:143926)
  6.   at process.onGlobalUncaughtException [as _fatalException] (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:363886)
  7.   at triggerUncaughtException (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:42:367400)
  8.   at processPromiseRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:1794051)
  9.   at processTicksAndRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:801887)
  10.   at _0x263935 (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:37:263515)

While doing npm start I'm getting the below problem:

  1. Server running at http://127.0.0.1:3000/
  2. Error: Invalid data
  3.     at writeJSON (file:///home/projects/stackblitz-starters-xzxhal/index.js:70:15)
  4.     at Server.eval (file:///home/projects/stackblitz-starters-xzxhal/index.js:24:15)
  5. TypeError [ERR_INVALID_ARG_TYPE]: The "chunk" argument must be of type string or an instance of Buffer or Uint8Array. Received an instance of Promise
  6.     at TypeError.get (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:385021)
  7.     at triggerUncaughtException (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:42:367449)
  8.     at processPromiseRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:1794051)
  9.     at processTicksAndRejections (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:35:801887)
  10.     at _0x263935 (https://stackblitzstartersxzxhal-cstc.w-credentialless.staticblitz.com/blitz.a19575a2.js:37:263515) {
  11.   code: 'ERR_INVALID_ARG_TYPE'
  12. }

Here's my index.js file code pieces:

  1. const server = http.createServer(async (req, res) => {
  2.     res.statusCode = 200;
  3.     res.setHeader('Content-Type', 'text/plain');
  4.     const dirPath = DIR_PATH + dirs[0];
  5.     const filePath = dirPath + './data.json';
  6.     let createdDirectoryIfNotExists = await createDirectoryIfNotExists(filePath);
  7.     if (createdDirectoryIfNotExists) {
  8.         res.writeHead(200, { 'Content-Type': 'application/json' });
  9.         res.write(writeJSON('./temp', contents));
  10.         res.end();
  11.     }
  12. });
  14. // write json in file
  15. const writeJSON = async (filePath, contents) => {
  16.     try {
  17.         if (contents && typeof contents === "object") {
  18.             const jsonString = JSON.stringify(contents);
  19.             // write file 
  20.             let isWriteFileSynced = fs.writeFileSync(filePath, jsonString, error => {
  21.                 if (error) {
  22.                     console.log(error);
  23.                 } else {
  24.                     return jsonString;
  25.                 }
  26.             })
  27.             if (isWriteFileSynced) {
  28.                 // read file after file is written
  29.                 let isReadFileSynced = fs.readFileSync(filePath, "utf8", (error, jsonString) => {
  30.                     if (error) {
  31.                         return false;
  32.                     } else {
  33.                         return jsonString;
  34.                     }
  35.                 })
  37.                 // if read file, return the jsonString
  38.                 if (isReadFileSynced) {
  39.                     return jsonString;
  40.                 }
  41.             } else {
  42.                 throw new Error("Invalid data");
  43.             }
  44.             return jsonString;
  45.         }
  46.     } catch (error) {
  47.         console.log(error);
  48.         return;
  49.     }
  51. };
  54. // create directory if not exists
  55. const createDirectoryIfNotExists = async (path) => {
  56.     fs.mkdirSync(path, { recursive: true });
  57.     return true;
  58. };

How to solve this issue?

答案1

得分: 1

Here is the translated code:

  1. 那个错误来自于`writeJSON`，它返回未解决的Promise，因此出现了错误
  3. 所以，你需要等待它：
  5. res.write(await writeJSON('./temp', contents));
  7. 但是，正如评论中指出的那样，你在函数内部使用了同步方法，所以不需要返回Promise，也不需要在`writeJSON`函数上使用`async`
  9. 此外，`fs.writeFileSync`不接受回调函数，它返回`undefined`，所以检查部分将始终失败。
  11. 它会抛出异常，因此你需要将`fs`的两个方法都包装在`try/catch`中，并从`try`部分返回JSON。
  13. 此外，不清楚为什么在之后读取文件，如果没有抛出异常，它就已经被写入了，但你可以重新组织一下：
  15. 这是一个应该可以工作的起始点（在某种程度上）：
  17. const writeJSON = (filePath, contents) => {
  18.   try {
  19.     if (contents && typeof contents === 'object') {
  21.       const jsonString = JSON.stringify(contents);
  23.       // 写入文件
  24.       try {
  26.         fs.writeFileSync(
  27.           filePath,
  28.           jsonString
  29.         );
  32.         // 文件写入后读取文件
  33.         let isReadFileSynced = fs.readFileSync(
  34.           filePath,
  35.           'utf8'
  37.         );
  40.         // 如果读取文件，返回jsonString
  41.         if (isReadFileSynced) {
  42.           return jsonString;
  43.         }
  45.       } catch (err) {
  46.         console.log(err);
  47.       }
  50.     } else {
  51.       throw new Error('无效的数据');
  52.     }
  54.   } catch (error) {
  55.     console.log(error);
  56.     return;
  57.   }
  58. };

修订后的测试通过的函数：

  1. const writeJSON = async (filePath, contents) => {
  2.  
  3.     if (contents && typeof contents === 'object') {
  4.       const jsonString = JSON.stringify(contents);
  6.       // 写入文件
  7.       try {
  8.         fs.writeFileSync(filePath, jsonString);
  10.         // 文件写入后读取文件
  11.         let isReadFileSynced = fs.readFileSync(filePath, 'utf8');
  13.         // 如果读取文件，返回jsonString
  14.         if (isReadFileSynced) {
  15.           return jsonString;
  16.         }
  17.       } catch (err) {
  18.         console.log(err);
  19.         // 待办事项
  20.         throw new Error('写入错误');
  21.       }
  22.     } else {
  23.       throw new Error('无效的数据');
  24.     }
  26. };
英文:

That error comes from writeJSON, which returns unresolved Promise, hence the error

So, you need to await it:

  1. res.write(await writeJSON('./temp', contents));

But, as pointed out in the comments, you use sync methods within the function, so no need to return a Promise, so no need to use async on writeJSON function

Also, fs.writeFileSync does not take a callback, and it returns undefined, so the check part will always fail.

It throws, so you need to wrap both fs methods in try/catch, and return json from the try part.

Also, not sure why you read the file afterwards, if it didn't throw, it's written but you can reorganize that:

Here's a starter that should work (somewhat):

  1. const writeJSON = (filePath, contents) => {
  2. try {
  3. if (contents && typeof contents === 'object') {
  4. const jsonString = JSON.stringify(contents);
  5. // write file
  6. try {
  7. fs.writeFileSync(
  8. filePath,
  9. jsonString
  10. );
  11. // read file after file is written
  12. let isReadFileSynced = fs.readFileSync(
  13. filePath,
  14. 'utf8'
  15. );
  16. // if read file, return the jsonString
  17. if (isReadFileSynced) {
  18. return jsonString;
  19. }
  20. } catch (err) {
  21. console.log(err);
  22. }
  23. } else {
  24. throw new Error('Invalid data');
  25. }
  26. } catch (error) {
  27. console.log(error);
  28. return;
  29. }
  30. };

edit

tests passing function:

  1. const writeJSON = async (filePath, contents) => {
  2. if (contents && typeof contents === 'object') {
  3. const jsonString = JSON.stringify(contents);
  4. // write file
  5. try {
  6. fs.writeFileSync(filePath, jsonString);
  7. // read file after file is written
  8. let isReadFileSynced = fs.readFileSync(filePath, 'utf8');
  9. // if read file, return the jsonString
  10. if (isReadFileSynced) {
  11. return jsonString;
  12. }
  13. } catch (err) {
  14. console.log(err);
  15. // todo
  16. throw new Error('err writing');
  17. }
  18. } else {
  19. throw new Error('Invalid Data');
  20. }
  21. };

huangapple
  • 本文由 发表于 2023年6月29日 15:47:51
  • 转载请务必保留本文链接：https://go.coder-hub.com/76579021.html
  • javascript
  • node.js
  • node.js-fs
  • readfile
  • writefile
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