javascript - Node .JS : How to make sure a reading stream has ended and the data written?

Question

所以我是 Node.js 上的 async/await 新手，我可以使用一些帮助来弄清楚此代码。

我正在尝试通过“ftp”包从 ftp 服务器获取文件，将数据写入本地“data.txt”并稍后在代码中打开它。我的问题是，在尝试使用 fs.readFileSync() 打开文件之前，我不明白如何确保文件完全写入“data.txt”中。

const ConfigFTP = require('./credentials.json')
const FtpClient = new ftpclient();


FtpClient.on('ready', async function() {
    await new Promise(resolve =>
      FtpClient.get('the ftp file directory', (err, stream) => {
        if (err) throw err;
        stream.once('close', () => {FtpClient.end();});
        // Stream written in data.txt
        const Streampipe = stream.pipe(fs.createWriteStream('data.txt')).on('finish', resolve)
      })
    )
})
FtpClient.connect(ConfigFTP);
var Data = fs.readFileSync('data.txt', 'utf8');

Answer 1

我不确定您想要完成什么，但您可以执行以下操作:

1)

const ConfigFTP = require('./credentials.json')
const FtpClient = new ftpclient()

let writeStream = fs.createWriteStream('data.txt')

FtpClient.on('ready', async function () {
    FtpClient.get('the ftp file directory', (err, stream) => {
            if (err) throw err
            stream.once('close', () => { FtpClient.end() })
            // Stream written in data.txt
            const Streampipe = stream.pipe(writeStream)
    })
})
FtpClient.connect(ConfigFTP)

writeStream.on('finish', () => {
    var Data = fs.readFileSync('data.txt', 'utf8')
})

2)

const ConfigFTP = require('./credentials.json')
const FtpClient = new ftpclient()


FtpClient.on('ready', async function() {
    await new Promise(resolve =>
      FtpClient.get('the ftp file directory', (err, stream) => {
        if (err) throw err
        stream.once('close', () => {FtpClient.end()})
        // Stream written in data.txt
        const Streampipe = stream.pipe(fs.createWriteStream('data.txt')).on('finish', resolve)
      })
    )
    var Data = fs.readFileSync('data.txt', 'utf8')
})
FtpClient.connect(ConfigFTP)