node.js - 下载并解压文件，然后检查内容，异步等待问题，node.js

Question

我正在下载 tar 格式的文件 request-promise模块。然后我使用 tar 解压该文件使用 async wait 语法的模块。

const list = new Promise(async (resolve, reject) => {
   const filePath = "somedir/myFile.tar.gz";
   if (!fs.existsSync(filePath)) {
     const options = {
        uri: "http://tarFileUrl",
        encoding: "binary"
     };

     try {
       console.log("download and untar");

       const response = await rp.get(options);
       const file = await fs.createWriteStream(filePath);
       file.write(response, 'binary');
       file.on('finish', () => {
         console.log('wrote all data to file');
         //here is the untar process
         tar.x(
           {
             file: filePath,
             cwd: "lists"
           }
         );
         console.log("extracted");
       });
       file.end();
     } catch(e) {
       reject();
     }
     console.log("doesn't exist");
  }
}

//here I am checking if the file exists no need to download either extract it (the try catch block)
//then the Array is created which includes the the list content line by line

if (fs.existsSync(filePath)) {
  const file = await fs.readFileSync("lists/alreadyExtractedFile.list").toString().match(/[^\r\n]+/g);

  if (file) {
    file.map(name => {
      if (name === checkingName) {
        blackListed = true;
        return resolve(blackListed);
      }
    });
  }
  else {
    console.log("err");
  }
}

console.log 输出序列如下:

download and untar
file doesn't exist
UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, open '...lists/alreadyExtractedFile.list'
wrote all data to file
extracted

因此文件 lists/alreadyExtractedFile.list 在创建之前会被检查。我的猜测是我做了一些错误的 async wait 操作。正如 console.logs 指出的那样，第二个检查 block 在某种程度上早于文件创建和解压过程。
请帮助我找出我做错了什么。

Answer 1

你的问题就在这里

  const file = await fs.readFileSync("lists/alreadyExtractedFile.list").toString().match(/[^\r\n]+/g);

readFileSync 函数不会返回 promise ，因此您不应等待它:

const file = fs.readFileSync("lists/alreadyExtractedFile.list")
    .toString().match(/[^\r\n]+/g);

这应该可以解决问题